Blood relation coded equation

For option A ($p \div q \times r$): $p \div q \implies p$ is mother of $q$ (female). $q \times r \implies q$ is daughter of $r$. Since $q$ is daughter of both mother $p$ and $r$, $r$ must be $q$'s father (husband of $p$). Thus $p$ and $r$ are wife and husband.