If Teenagers and Adults Are Substitutes in Production,and the Wage

Multiple Choice

If teenagers and adults are substitutes in production,and the wage of teenagers falls,then

A) they must be gross substitutes, and the employment of adults will fall.
B) they must be gross complements, and the employment of adults will fall.
C) they could be either gross substitutes or gross complements, and the employment of adults could rise or fall.
D) they must be gross substitutes, and the employment of adults will rise.