Is It a Valid Defense for a Seller to Engage

Is it a valid defense for a seller to engage in price discrimination in order to compete in good faith with another seller's low price?

A) No, that is not a defense, and the seller has violated the Clayton Act.
B) No, that is not a defense, and the seller has violated the Sherman Act.
C) Yes, that is a valid defense to price discrimination called the meeting-the-competition defense.
D) Yes, that is a valid defense to price discrimination called the legitimate-price-discrimination defense.
E) Yes, that is a valid defense to price discrimination called the meet-the-offense defense.