Ps father is Qs son. M is the paternal uncle of P and N is the Brother of Q. How is N related to M ?

Ps father is Qs son. So, Q is Ps grandfather. M is the paternal uncle of P. So M is the brother of Ps father. This means that M is also Qs son. N is the brother of Q. Because Qs gender is not specified therefore correct answer is option 4.