Read the following statements and answer the following question.
A4B means A is the mother of B
A3B means A is the father of B
A5B means A is the son of B
A7B means A is the daughter of B
Which of the following equation shows "P's father is the grandfather of S"?

A

P5Q5R4S

B

P7Q5R4S

C

P4Q4R7S

D

P7Q3R4S