The correct option is A 13
An exterior angle of (n−1) sided regular polygon = 360o(n−1)
An exterior angle of (n+2) sided regular polygon = 360o(n+2)
Their difference is 6o
So,
360o(n−1)−360o(n+2)=6o
=>60(n+2)−(n−1)(n−1)(n+2)=1
=>(n−1)(n+2)=180
=>n2+n−2=180
=>n2+n−182=0
=>n2+14n−13n−182=0
=>(n−13)(n−14)=182
=>n=13,−14
Since n should be a positive number. So,n=13