Marilyn and tiara went for jogging every day. they increased the number of minutes of jogging every week as described below: marilyn: jogged for 10 minutes every day in the first week, 20 minutes in the second week, 40 minutes in the third week, and 80 minutes in the fourth week. tiara: jogged for 10 minutes every day in the first week, 20 minutes in the second week, 30 minutes in the third week, and 40 minutes in the fourth week. which statement best describes the methods used by marilyn and tiara to increase the time they spent jogging?
a.) marilyn's method is linear because the number of minutes increased by an equal factor every week.
b.) tiara's method is linear because the number of minutes increased by an equal number every week.
c.) both tiara's and marilyn's method is exponential because the number of minutes increased by an equal number every week.
d.) both tiara's and marilyn's method is exponential because the number of minutes increased by an equal factor every week.