The Case in Point on the Production of Fitness Made

The Case in Point on The Production of Fitness made the point that:

A) when it comes to fitness, more exercise always generates increasing marginal benefits.
B) working out every day is better than taking a day or two off when it comes to building up aerobic capacity.
C) the law of diminishing returns applies to athletic training.
D) the law of diminishing returns doesn't apply to aerobic exercise.