AMC 8 1989 Problem 10

What is the number of degrees in the smaller angle between the hour hand and the minute hand on a clock that reads seven o'clock? $\text{(A)}\ 50^\circ \text{(B)}\ 120^\circ \text{(C)}\ 135^\circ \text{(D)}\ 150^\circ \text{(E)}\ 165^\circ$