If the Marginal Cost of Producing an Extra Million Kilograms

If the marginal cost of producing an extra million kilograms of french fries is $1 million, then McCain Foods Ltd.should produce the extra french fries

A) only if the marginal benefit is greater than $1 million plus an acceptable profit margin.
B) as long as the marginal benefit the firm receives is just equal to or greater than $1 million.
C) as long as the marginal cost does not rise.
D) until the marginal benefit the firm receives reaches zero.