A group of private investors borrowed $30 million to build 300 new luxury apartments near a large university. The money was borrowed at 6% annual interest, and the loan is to be repaid in equal annual amounts over a 40-year period. Annual operating, maintenance, and insurance expenses are estimated to be $4,000 per apartment. This expense will be incurred even if an apartment is vacant. The rental fee for each apartment will be $12,000 per year. What is the minimum occupancy rate that would make this investment feasible? (Choose the closest occupancy rate from the answers)

a. 80% b. 95% c. 75% d. 90% e. 85%