sir i am stuck for this question

Suppose the cost of operating a 100 room hotel for a night is $10,000 and there are 5 empty rooms for tonight. If the marginal cost of operating one room for one night is $30 and a customer is willing to pay $60 for the night, the hotel manager should @ a. rent the room because the marginal benefit exceeds the average cost. O b. rent the room because the marginal benefit exceeds the marginal cost. @ c not rent the room because the marginal benefit is less than the average cost. Od. not rent the room because the marginal benefit is less than the marginal cost. A key determinant of the price elasticity of supply is the a. extent to which buyers alter their quantities demanded in response to changes in their incomes. b. number of close substitutes for the good in question. O c. length of the time period. O d. extent to which buyers alter their quantities demanded in response to changes in prices