Students guess that Norb's age is $28$, $30$, $34$, $36$, $38$, and $41$. Norb says, "At least half of you guessed too low, two of your guesses are off by one, and my age is a prime number."~How old is Norb? (adapted from 2011 AMC 8 Problem, Question \#21) 
选项为:A:$$25$$  B:$$29$$  C:$$31$$  D:$$37$$  E:$$14$$  请回答其中一个选项.