Answer
The potential energy is proportional to $(h-h_{0})$
So, if we want to give positive value to the expression, then we should set the reference height lower than the position of the object, so that $h>h_{0}$.
Work Step by Step
The potential energy is proportional to $(h-h_{0})$
So, if we want to give positive value to the expression, then we should set the reference height lower than the position of the object, so that $h>h_{0}$.
