You should be doing your own homework, not us! You won't learn by having someone else do it for you. Now go study!
So I got a thumbs down because I wouldn't answer a silly question, wow, you people have no sense of humor whatsoever. The answer is A.
Clear Blue.
I got a positive the first day with a Digital Clear Blue.
I used a First Response twice the next week (just to be sure) and both said negative. They were wrong. I'm 13 weeks pregnant.
Yes, they work. I got a BFP from a dollar store brand, and a negative from a First Response. (I'm 13 weeks and 3 days pregnant).
If you are still worried, wait another week and test again, or go to your doctor.