Bennie's Top Factory Produces 1,000 Tops Per Day for a Total

Bennie's Top Factory produces 1,000 tops per day for a total daily revenue of $2,000.Bennie's total costs would rise by $2 if it produced the 1,001^st top.Because marginal revenue and price are equal and constant,

A) profit would rise by $2 if Bennie produced one additional top
B) profit would fall by $2 if Bennie produced one additional top
C) profit would not change if Bennie produced one additional top
D) profit will fall by some unknown amount if Bennie produced one additional top
E) the total cost curve must have shifted to the left