A Short- Run Average Total Cost Curve and a Long-

Multiple Choice

A short- run average total cost curve and a long- run average cost curve are tangent

A) where the short- run cost curve is downward sloping.
B) by coincidence.
C) where the short- run cost curve is upward sloping.
D) when the quantity of the fixed factor is at the optimal level for that level of output.
E) where the short- run cost curve is downward- sloping and the quantity of the fixed factor is optimal.