Cardio coasting is detrimental to a fitness routine because

Athe lack of variation in activity can lead to boredom and eventually cause exercise to stop.
Bit can cause extreme weight gain.
Cit can increase the chance of injury.
Dit can increase the chance of a heart attack.

Verified Answer :

I chose a. the lack of variation in activity can lead to
boredom and eventually cause exercise to stop. Your body will get use to
the same routine and would no longer be pushed to another level.  You have to try new exercises that would
boost your cardio without necessarily overworking yourself.

Took the test and got 100.
The answer is A. the lack of variation in activity can lead to boredom and eventually cause exercise to stop.