Which characteristic best distinguishes runoff and infiltration?

Runoff describes the movement of water, while infiltration describes storage of water. Runoff is the part of irrigation, precipitation, or snowmelt, which flows overland as surface water instead of evaporating or infiltrating. The factors which affect runoff are the amount of rainfall, permeability, vegetation, and slope.  

On the other hand, infiltration refers to the procedure by which precipitation or the water on the surface of the ground moves within the soil. The factors, which predict the rate of infiltration comprise the topography of the land, type of soil, vegetation, amount of precipitation, and pre-saturation levels.  

1. (1.2kw)x(15/60hours) = .3kwh --> a

2. (5kw)x(90/60hours)x(8cents/kwh) = $0.60 --> d

3. microwave --> 1200 watts = (1.2kw)x(6/60hours) = .12kwh

coffee-maker --> 900 watts = (.9kw)x(10/60hours) = .15kwh

therefore, it requires more energy for the coffee-maker to do the same amount of work.

so the answer is a.