Nancy Stone has a small company and has negotiated a special rate for rental cars when she and other employees take business trips. The maximum charge is $45.00 per day plus $0.40 per mile. Discounts apply when renting for longer periods of time or during off-peak seasons.

Write a linear inequality that models the total cost of the daily rental c(m) as a function of the total miles driven, m.

a. c(m) ≤ 45 + 0.4m
b. m > c(m) +45
c. m < c(m) +45
d. c(m) ≥45+ 0.4m
please help