<image>In the rectangular parallelpiped shown, $AB = 3, BC= 1,$ and $CG = 2$. Point $M$ is the midpoint of $\overline{FG}$. What is the volume of the rectangular pyramid with base $BCHE$ and apex $M$?
A. $1$
B. $\frac{4}{3}$
C. $\frac{3}{2}$
D. $\frac{5}{3}$
E. $2$