Final answer:
The domain of M(c) is the set of whole numbers from 0 to 80, as this represents the range of possible customers the theater can accommodate on a Sunday night.
Step-by-step explanation:
The function M(c) = 7.5c represents the money the theater makes on Sunday nights, where c is the number of customers and M(c) is the total money made.
The domain of M(c) in this context refers to the set of all possible values of c that are applicable within the situation defined by the theater's capacity.
Since the theater can hold a maximum of 80 customers and cannot have a negative number of customers, the domain is the set of whole numbers from 0 to 80, inclusive.