Suppose That the Incumbent and the Entrant in the Long-Distance

Suppose that the incumbent and the entrant in the long-distance phone call market compete in prices (rates) . Then,                                         _.

A) under the ECPR, only entrants with unit cost ?E > ?I will enter the long- distance phone-call industry.
B) under the ECPR, only entrants with unit cost ?E < ?I will enter the long-distance phone-call industry.
C) under the ECPR, only entrants with unit cost ?E ? ?I will enter the long-distance phone-call industry.
D) under the ECPR, only entrants with unit cost ?E = ?I will enter the long- distance phone-call industry.