When new firms enter a competitive market, because existing firms are making economic profit, the market supply a. decre

[answerhappygod]

When new firms enter a competitive market, because existing
firms are making economic profit, the market supply
a.
decreases and existing firms' MR curves shift upward
b.
increases and market demand shifts down
c.
increases and existing firms' MR curves shift down
d.
increases and firm demand increases.