When the Average Total Cost Curves for Firms Are Unaffected

When the average total cost curves for firms are unaffected by the entry of other firms,

A) it is an increasing-cost industry
B) it is a decreasing-cost industry
C) the market's equilibrium price will eventually be restored after the market demand increases
D) firms will charge a higher price when demand rises
E) the long-run supply curve is positively sloped