Answer: Add an extra day of walking each week (option c)
Explanation:
The FITT program stands for frequency, intensity, time and type. Frequency is how often or how many times you exercise per week. Intensity is how hard you exercise. Time is the amount of time that you spend exercising and type is simply the type of exercise that you choose to perform. So, if Trey’s family wants to improve they should increase the frequency according to the FITT cycle .