At the​ profit-maximizing level of​ output, what is the relationship between the total revenue​ (TR) and total cost​ (TC) curves? A. They cannot be tangent to each other. B. They must have the same slope. C. They must​ intersect, with TC cutting TR from above. D. They must​ intersect, with TC cutting TR from below. E. They must be tangent to each other.