AMC 8 1996 Problem 5

The letters $P$, $Q$, $R$, $S$, and $T$ represent numbers located on the number line as shown.

Which of the following expressions represents a negative number? $\text{(A)}\ P-Q \text{(B)}\ P\cdot Q \text{(C)}\ \dfrac{S}{Q}\cdot P \text{(D)}\ \dfrac{R}{P\cdot Q} \text{(E)}\ \dfrac{S+T}{R}$