KöMaL 2022 C1736

Let $P$ be an interior point of side $CD$ of a parallelogram $ABCD$, and let $Q$ be an interior point of side $AB$ (being parallel with $CD$). The line segments $PA$ and $QD$ intersect each other at $M$, while the line segments $PB$ and $QC$ intersect each other at $N$. Find a condition to have $MN\parallel{AB}$.