The function f(x) = −23x + 4 represents the average number of teacher absences due to illness, f(x), when the school uses x bottles of hand sanitizer per month. What is a reasonable domain for the function in this situation?
A. x ≤ 6
B. 0 ≤ x ≤ 6
C. 0 ≤ x ≤ 4
D. all real numbers