Suppose the Production of Long-Distance Airline Flights Is Described by a Fixed

Suppose the production of long-distance airline flights is described by a fixed proportion production process in which three crew members (i.e., labor) are required for each aircraft (i.e., capital) . If the airline operates with four crew members per plane, then we know that:

A) the production process violates diminishing margin returns.
B) production at this point is technically inefficient.
C) the isoquants for this production process are upward sloping.
D) the airline will have negative profits.