19. $P Q R S$ is a square. Point $T$ lies on $P Q$ so that $P T: T Q=1: 2$. Point $U$ lies on $S R$ so that $S U: U R=1: 2$. The perimeter of $P T U S$ is $40 \mathrm{~cm}$.
What is the area of PTUS?
A $40 \mathrm{~cm}^{2}$
B $45 \mathrm{~cm}^{2}$
C $48 \mathrm{~cm}^{2}$
D $60 \mathrm{~cm}^{2}$
E $75 \mathrm{~cm}^{2}$