A company is selecting students for interviews at the career fair. The number of students selected from university A is given by f(x) = 4x + 5, where x represents the number of days of the fair. The number of students selected from university B is given by g(x) = 2x + 8. Which function best describes the total number of students selected at the career fair?
a. h(x) = (4x + 5)(2x + 8)
b. h(x) = 2x - 3
c. h(x) = -2x + 3
d. h(x) = 6x + 13