Each of $P, Q, R, S, W, X, Y$and $Z$ has been married at most once. $X$ and $Y$ are married and have two children $P$ and $Q. Z$ is the grandfather of the daughter $S$ of $P$. Further, $Z$ and $W$ are married and are parents of $R$. Which one of the following must necessarily be FALSE?
Let $\to$ represent the child relation.
Correct Option: D