The gotchas with these 'duration of' questions is that some entitlements run for X days, some run for X months, and some run for X calendar months. On the last one, an entitlement obtained on say the 15th of the month runs until the last day of the month of expiry. A real sod to remember. Especially as some of the 'X days' entitlements don't start counting the days until the first day after the entitlement was obtained.
Of course the questions are phrased to trap the common and easy misunderstandings. The #1 job with CAA exams especially is to read the Q several times.