Ans: B
Note that the volume is conserved. Then we have
Note that the volume is conserved. Then we have
$\begin{array}{rcl}
\dfrac{1}{2} \times \dfrac{4}{3} \pi r^3 & = & 3 \times \dfrac{1}{3} \pi r^2 h \\
\dfrac{2}{3} r & =& h \\
\dfrac{r}{h} & = & \dfrac{3}{2} \\
r : h & = & 3 : 2
\end{array}$
