Answer
The correct answer is (d) m
Work Step by Step
$U = mgh$
Let x be the units of $h$.
$kg\cdot m^2 \cdot s^{-2} = (kg)(m\cdot s^{-2})(x)$
$x = \frac{kg\cdot m^2 \cdot s^{-2} }{(kg)(m\cdot s^{-2})} = m$
The units of $h$ are m (and note that m stands for meters.)
The correct answer is (d) m
