In general, which factor is not critical when beginning an exercise program?
a.
using appropriate protective equipment during exercise
b.
finding friends who like to exercise the same way you do
c.
seeing your doctor for a physical assessment prior to beginning exercise
d.
choosing clothing that is designed to match your exercise program

B.finding friends who like to exercise the same way you do

Explanation:

Not mandatory, or not necessary are two very close things, finding friedns that like to exercise the same way as you do could be important and helpful on your exercising habits, but without this you can still go out and exercise, if you do not check with the doctor first which exercises can harm you, you could injure yourself, as well as when not using appropraite protective equipment or clothing that is designed to match your exercise, so the only one that is not necessary would be B.finding friends who like to exercise the same way you do

this is really easy just look up what these words mean