Why might it be bad for hotels to not charge higher prices when rooms are in higher demand?

a. Arbitrageurs might establish a black market by reserving rooms and then selling the reservations to customers.

b. Rooms may be rationed.

c. Without the profit from these high demand times, hotels would have less of an incentive to build or expand, making the long-run scarcity problem even worse.

d. All of the above.