The smaller angle is $\frac 5{12}$ of a full circle.  A full circle has $360$ degrees, so the angle is $\frac 5{12}\times 360^{}\circ =150^{}\circ $.  So, the answer is $\rm D$. 
What is the angle between the hour hand and the minute hand at seven o\textquotesingle clock? ． 
(a) $50^{}\circ $ 
(b) $120^{}\circ $ 
(c) $135^{}\circ $ 
(d) $150^{}\circ $ 
(e) $165^{}\circ $ 