The term duration refers to
a. how strenuous a workout is.
b. how much sweat is lost during a workout.
c. how many times per week a person exercises.
d. how long a workout or exercise lasts.

The question is asking us to define the term "duration" when used for exercise - and in fact it is d. how long a work out or exercise lasts. For exmple, a duration of an exercise could be 90 minutes and the fruquency, that is how often you exercise, could be twice a week (this would be c, so if the question was asking for frequency, we would answer C)

Positive roles models does great things and novitiate people bad role models does bad things

Role models are really important too, because they influence you.