In coded relation type questions, the relationships are represented by certain codes or symbols such as + , - , ÷ , × , * etc. Then relationships between certain persons, given in the form of these codes, are to be analysed.
A + B means A is the son of B;
A - B means A is the wife of B;
A x B means A is the brother of B;
A ÷ B means A is the mother of B; and
A = B means A is the sister of B.
What does P + R - Q mean ?
Clearly, P + R - Q means, P is the son of R who is the wife of Q i.e. Q is the father of P.
Hence, the answer is (a).