Step 1: Concept
Gravitational potential energy ($U$) is the energy possessed by an object due to its position in a gravitational field.
Step 2: General Formula
For two point masses $M$ and $m$ separated by distance $r$, $U = -\frac{GMm}{r}$.
Step 3: Application to Earth
On the surface of the Earth, the distance from the center of mass is equal to the radius $R$.
Step 4: Conclusion
Substituting $r = R$, we get $U = -\frac{GMm}{R}$.
Final Answer: (A)