#2 The CORRECT ANSWER is February and the reason is because in the question you state "Some months have 31 day, others have 30" and that "others" differentiates between the 30 day months and the 31 day months. ERGO, by your own wording and precedence, 28 day months are also separate and only February meets that criteria. EVERYONE WHO SAID FEBRUARY FOR NO.2 COUNT THAT AS CORRECT !!!