Synonyms - Verbal and Reasoning

Directions to SolveIn each of the sentences given below a word is printed in bold. Below it four choices are given. Pick up the one which is most nearly the same in meaning as the word printer in bold and can replaces it without altering the meaning of the sentence.
Q1:

Only those who are gullible take every advertisement seriously.

A fallible

B enthusiastic

C unsuspecting

D unrealistic

ANS:C - unsuspecting

No answer description is available.