The answer is a.12.5kg because i just did the test and it was correct.
hope this helps
The kinetic energy is

and the height of the building doesn't matter at all.

joules
In order to calculate the amount of energy required, we must first check the latent heat of vaporization of water from literature. The latent heat of vaporization of any substance is the amount of energy required per unit mass to convert that substance from a solid to a liquid. For water this is 2,260 J/g. We now use the formula:
Energy = mass * latent heat
Q = 50 * 2,260
Q = 113,000 J
113,000 Joules of heat energy are required.
Either one is fun and great to play!
Answer: 4
Explanation: speed= distance/time