Answer:
A. rent the room because the marginal benefit exceeds the marginal cost.
Step-by-step explanation:
As the marginal benefit of renting out a room exceeds the marginal cost of operating the same room (MB>MC), its means that we gain from operating each room when we compare marginal benefit with marginal cost. In this situation, the resource of the hotel will be more efficiently utilised when more rooms are rented out.