Melissa exercises for 20 minutes every day. she decides to increase her daily exercise time by 5 minutes each week. however, according to her doctor’s orders, she can spend no more than 45 minutes a day exercising. for how many weeks can melissa increase her exercise time this way?
a. at least 13 weeks
b. at most 5 weeks
c. at most 13 weeks
d. at least 5 weeks