If $$X \times Y$$ means that X is the mother of Y, $$X - Y$$ means that X is the father of Y, $$X \div Y$$ means that X is the sister of Y, then which of the following expression shows that P is the paternal grandfather of R?

A

$$P - Q \div R$$

B

$$P \times Q - R$$

C

$$P - Q \times R$$

D

$$Q - P \times R$$