Data Sufficiency

Statement 1 : if he paid 595 that means he paid 35% of 1700 as a penalty. That means he cancelled the trip sometime between 45 to 31 days prior ; not sufficient
Statement 2 : if the price would increase 255 that means it would increase 15% more. Let's check the penalty table. There are two cases where a 15% change happens. (from 35 to 50 and 50 to 65); not sufficient.

Statements 1 & 2 : Combined together they let us solve the question. He cancelled on 31 days prior

Answer is C.

mastak.kaur wrote:Thanks for the explanation. I just realised a big calculation error I made. It all makes sense now.

no worries glad you got it sorted out.