Benhamin is a miliner$-$that is$,$ he disgns, makes, and sells women's hats. Currently, he sells just enough hats that his economic profits are zero. In other words, his total revenue equals:

a$.$ the financial cost of running the business

b$.$ what he could earn in any alternative profession for which he's suited

c$.$ the financial cost of running the business minus what he could earn in any alternative profession for which he's suited

d$.$ the financial cost of running the business plus what he could earn in any alternatice profession for which he's suited