There are a lot of burning questions that need to be answered on Pretty Little Liars, but the most pressing mystery heading into the Season 7 summer finale is: Who is Mary Drake's (Andrea Parker) missing child?

There have been several clues dropped in the first half of Season 7 about who the missing Drake child could be. We know that Mary's second child is younger than her oldest, Charlotte (Vanessa Ray), and was adopted after Mary gave birth in Radley Sanitarium — making him or her about the Liars' age. Noel Kahn's (Brant Daughtery) father is also the judge that approved the adoption.

We've compiled the evidence and put together our best guesses as to who "the missing Drake" could be.

Pretty Little Liars will end with Season 7

4. Noel Kahn

Why it could be: Noel Kahn has been the main suspect as the missing Drake since he arrived back in Rosewood. His allegiance with Jenna (Tammin Sursok) and the video evidence that he helped Charlotte with the doll house doesn't help things either. It would also be convenient since his father is the one that approved the adoption. Since we know he'll be tormenting the girls once again in the summer finale, could it all be to confirm that he's Mary's missing son?

Why he's not it: Pretty Little Liars lives for the misdirect, and all signs pointing to Noel Kahn is the biggest indication that it's not him. How lame would it be if the reveal was something we've basically already been told?

Brant Daughtery and Tammin Sursok, <em>Pretty Little Liars</em>Brant Daughtery and Tammin Sursok, Pretty Little Liars

3. Jenna Marshall

Why it could be: Jenna will be helping Noel stalk the Liars, and she's had it out for the girls since Day 1. It was revealed earlier in the season that she had mysteriously become friends with Charlotte while the former-A was in the hospital. In fact, Jenna is the one that helped Charlotte get with Archer Dunhill (Huw Collins). Why would she strike up a relationship with Charlotte unless she had found out they had a familial connection?

Why she's not it: The first tell is that Jenna has no physical resemblance to the Drakes or the DiLaurentis family. The black hair and green eyes would make her stick out like a sore thumb. She's also too close to obvious to be a real shocker for the fans to find out. Does Jenna have a secret? Most definitely, but it's just hard to believe that it's this one.

Pretty Little Liars: Troian Bellisario once got into a fight with a fan over who really plays Spencer Hastings

2. Spencer Hastings

Why it could be: After the Liars found out that Mary Drake had a second baby while she was in Radley, Spencer (Troian Bellisario) decided to go flipping through her family photo album. At first, it just seemed like a stroll down memory lane, but as Spencer flipped through the pages, there were no obvious photos of Spencer as a baby. Let's face it, this wouldn't be the first time that the Hastings have kept a secret about their children.

Plus, we already know that Spencer's father had a child with Jessica DiLaurentis — Mary's twin sister. Maybe he hooked up with Mary, thinking it was Jessica, and then adopted the child since he'd already given up being Jason's (Drew Van Acker) father.

Why she's not it: The logistics make sense, but would PLL go back to the same story well if the DiLaurentis/Drake and Hastings family already have a sordid history when it comes to biological children? This definitely feels like the type of thing Melissa (Torrey DeVitto) would have brought up or rubbed in Spencer's face in the past.

Pretty Little Liars: Aria and Jason's secret revealed!

1. Aria Montgomery

Why it could be: A.D. took two files the night they burned Jessica DiLaurentis' secret basement hideout on fire — Noel Kahn's and Aria Montgomery's (Lucy Hale). We have yet to find out why Aria would be of special importance to A.D. over the other girls. If that folder confirmed that Aria was really the daughter of Mary Darke, it'd make a lot of sense why A.D. would go to such extreme lengths to stop the girls from finding out.

Why she's not it: There's really not a lot of argument for why Aria couldn't be the missing Drake. It would be a huge reveal that no one saw coming — and a heartbreaking twist heading into the second half of the season. Will she still feel like walking down the aisle with Ezra (Ian Harding) if she suddenly has doubts about who she really is? That's a delicious conundrum, and why we think she'd be the best possible choice to be the missing Drake.

Pretty Little Liars' summer finale airs Tuesday, Aug. 30 at 8/7c on Freeform.