Answer:
The domain would be the set of all whole numbers.
Explanation:
Integers are { ......-3, -2, -1, 0, 1, 2, 3....}
Whole numbers are {0, 1, 2, 3, ...... }
Real numbers are all numbers except imaginary number,
Positive integers are {1, 2, 3, 4, ....}
Given,
In the function f(x),
x represents the number of people in line,
We know that number of people can not be negative and it can be 0,
Thus, the possible value of x are 0, 1, 2, 3,......
Also, the domain of a function is the set of all possible value of input,
Since, x represent the input for the function f(x),
Thus, the domain of f(x) would be the set of all whole number.
Second option is correct.