Volume of the given rectangular prism is cu units.

The correct option is B 9
Volume of a rectangular prism
= length $\times$ breadth $\times$ height

Length of the given prism = 3 units
Breadth of the prism = $2\frac{1}{4}$ units
Height of the prism = $1\frac{1}{3}$ units

$\therefore$ Volume of the given prism
$=3\times 2\frac{1}{4}\times 1\frac{1}{3}$
$=3\times \frac{9}{4}\times \frac{4}{3}$
= 9 cu units