Tarco Is a Manufacturer and National Distributor of Spark Plugs

Tarco is a manufacturer and national distributor of spark plugs.It charges $8 per set for its plugs.Reemco manufactures and distributes spark plugs on the East Coast.In order to get customers away from Tarco,Reemco sells its plugs in New York City for $7 per set.Tarco learns of this and drops its prices to $7 per set only in New York.A Los Angeles customer of Tarco learns of this and sues Tarco for price discrimination.What is the most likely outcome?

A) This is legal because of cost justification.
B) This is legal because of changing conditions.
C) This is legal because of meeting the competition.
D) This is illegal price discrimination.