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?． 
Options:
[A] $50^{}\circ $ 
[B] $120^{}\circ $ 
[C] $135^{}\circ $ 
[D] $150^{}\circ $ 
[E] $165^{}\circ $ 