To Answer,refer to the Following

Multiple Choice

To answer,refer to the following:
"At Huffy's ...bicycle factory,1,700 employees turn out 15,000 bicycles a day.Five years ago,it required 2,200 workers to make 10,000 bikes daily."
Holding all else equal,we can conclude that,over the past 5 years,

A) Huffy's average variable cost decreased.
B) Huffy's average variable cost increased.
C) Huffy's marginal cost decreased.
D) Huffy's marginal cost increased.
E) both a and c