I am stuck on a homework question. The answer key says one thing and I get another answer. Can you help explain?

A stone is held at a height h above the ground. A second stone with four times the mass of the first one is held at the same height. The gravitational potential energy of the second stone compared to that of the first stone is ...

I keep getting:

One-fourth as much

The answer key says four times as much.

Can you explain why?