Five students Adele, Betty,Carol, Doris, and Ellen- answered five questions on an exam consisting of two multiple-choice (a,b,c) questions and three true-or-false questions.

(1) They answered the questions as follows:

I II. III. IV. V
Adele. a a t t t
Betty. b b t f t
Carol. a b t t f
Doris. b c t t f
Ellen. c a f t t

(2) No two students got the same number of correct answers.

Who got the most correct answers?