Use the information to answer the following question. A local theater sells admission tickets for $9.00 on Thursday nights. At capacity, the theater holds 100 customers. The function M(n) = 9n represents the amount of money the theater takes in on Thursday nights, where n is the number of customers.

What is the domain of M(n) in this context?

A.
all whole numbers

B.
all non-negative rational numbers

C.
all non-negative integers that are multiples of 9

D.
all non-negative integers less than or equal to 100