Correct option is D
Given,
‘M & N’ means ‘M is the wife of N’,
‘M @ N’ means ‘M is the brother of N’,
‘M $ N’ means ‘M is the daughter of N’,
‘M # N’ means ‘M is the son of N’.
Logic:

Explanation:
N # M @ O $ P & Q

So, Q is N’s Father’s father.