An antique music store sells two types of vinyl records; \(45 \mathrm{rpm}\) records \((f)\) and \(33 \mathrm{rpm}\) records ( \(t\) ). It makes a profit of \(\$ 2.50\) for each \(45 \mathrm{rpm}\) record and \(\$ 6.75\) for each \(33 \mathrm{rpm}\) record. The objective function for profit in this situation is:

a. \(P=2.50 f+6.75 c\)

b. \(P=2.50 f+6.75 t\)

c. \(P=2.50 t+6.75 f\)

d. None of these