69. Although she had signed a pledge of abstinence while being an adolescent. Frances Willard was 35 years old before she chose to become a temperance activist.
(A) while being an adolescent
(B) while in adolescence
(C) at the time of her being adolescent
(D) as being in adolescence
(E) as an adolescent
Key is E. But I can not figure out why B is not correct. "while (she was )in adolesence" should have no grammar fallacy. | 
