1. Which of the following items is an example of direct costs?
a. The cost of lumber used in building a structure
b. Lease payments for office space
c. Cost of heating and air conditioning
d. Salaries of supervisors, secretaries, and attorneys
2. In principle, the salary paid a worker should be:
a. less than the required level of profit
b. equal to minimum wage requirements
c. determined by opportunity costs of the investment opportunity
d. less than the worker's value marginal product