What can we say about Constant Returns To Scale?

Multiple Choice

A. This is the point where Average Product = Marginal Product.
B. This is the point where you are minimizing the Marginal Cost Curve.
C. This is the point where Marginal Cost = Total Average Cost.
D. The firm is operating at the flat level at the bottom of the Long Run Average Total Cost Curve. Costs are not rising nor falling as they increase production.