Read the following statements and answer the following question.

A4B if B is the mother A is
A3B if B's ​​father A is
A5B if B's ​​son A is
A7B If B's ​​daughter A is in the

following equation, what is the 'S's father'?

A

P5Q5R4S

B

P7Q5R4S

C

P3Q3R7S

D

P4Q3R7S