The correct answer is A) Power. Power is defined as the rate of doing work, which means the amount of work done per unit of time. This is the fundamental definition of power in physics and engineering. The other answer choices are not the correct definition of power - kinetic energy and potential energy are forms of energy, mechanical work is the transfer of energy, but power is the rate at which that work is done. So in the context of a US Coast Guard Captain's License Examination, the term that is defined as the rate of doing work would be power.