What term describes the amount of light reflected from a surface, measured in lumens per square foot?

The correct term that describes the amount of light reflected from a surface, measured in lumens per square foot, is foot-candle. A foot-candle quantifies illumination. It specifically refers to the illumination received on a surface that is one foot away from a uniform light source, where one lumen is distributed over one square foot. So, if you have a surface with a certain amount of light reflected off of it, measuring it in foot-candles allows you to understand how much light is being reflected in relation to the area of that surface.

Footlambert, on the other hand, measures luminance rather than illuminance, which is about the brightness of the surface itself rather than the light that falls upon it. Lux is the metric unit for illuminance, equivalent to one lumen per square meter, while watt measures power rather than light or illumination. Thus, foot-candle is specifically the term used for measuring how much light is reflected off a surface, making it the correct choice in this context.