During the wettest period since they started keeping records in 1877, a 25 foot boulder fell in a mudslide and blocked both lanes of topanga canyon road in malibu, california in january 2005. what was the initial transfer of energy that accelerated the boulder down the side of the mountain?

This had choices. They were:
A. potential energy being converted into mechanical energy
B. potential energy being converted into kinetic energy
C. kinetic energy being converted into potential energy
D. mechanical energy being converted into potential energy 

The answer is B. POTENTIAL ENERGY BEING CONVERTED INTO KINETIC ENERGY

Potential energy is greater the higher an object is from the Earth. Potential energy was converted into kinetic energy as the boulder broke free from the mountain and began to move.