If the elasticity of substitution of a production function is equal to zero, then this production function is a

If wages for a certain type of labor were higher in one market than in another, then

A) the differential would exist into the long run. B) labor would move from the high wage market to the low wage market until wages were equal. C) labor would move from the low wage market to the high wage market until wages were equal. D) firms would not be acting as profit maximizers.

All the following are examples of variable costs, except

a. Labor costs b. Cost of raw materials c. Accounting fees d. Electricity costs