UKMT Junior Mathematical Challenge, 2017

The diagram shows a rectangle $PQRS$ and $T$ is a point on $PS$ such that $QT$ is perpendicular to $RT$. The length of $QT$ is 4 cm. The length of $RT$ is 2 cm. What is the area of the rectangle $PQRS$?

(A) $6\text{ cm}^2$ (B) $8\text{ cm}^2$ (C) $10\text{ cm}^2$ (D) $12\text{ cm}^2$ (E) $16\text{ cm}^2$