PRETTY LITTLE LIARS THEORY
Holden is not A. Holden had a bruise on the right side of his body. Many people thought this was when Hanna hit A with her car. BUT, Hanna hit A on the LEFT side. My guess is that either A) Holden is getting abused at home and is going out with Aria to get away from his parents. B) He is being bullied into doing something, Possible by A, Or C) His family is having a tough time after moving back from Iceland and he is fighting for money.
Secondly, I personally think Jenna is A, and that Jenna is Ali's twin. I have another post on my profile with that theory if you want to read it. First, they showed Jenna with a blonde wig in the halloween episode. In the last episode, they showed Ali with a brown wig. I think the produces are doing this to let viewers get a feel for how much Alison and Jenna look alike. Also, when they showed the fake I.D, someone (don't remember who) asked if it was a picture of Jenna before figuring out that it was Ali.
And Jenna is not blind. I believe she was at one time, but not anymore. In last monday's episode, Jenna adressed Spencer withought Spencer saying anything in advance. In one episode, Spencer was looking at yearbooks and Jenna somehow knew about it. Also, do you notice her putting on lipstick in random episodes? One time she was putting lipstick on while looking in the elevator. Why would she need to look into the reflection if she was blind?