Answer:
A. Ranging from 50% to 90% of your maximum heart rate.
Explanation:
The lower and upper limits of the target heart rate is defined by taking the 50% and the 90% of the maximum heart rate.
The target heart rate when doing exercise is the heart rate that is thought to be ideal when doing different things, it is a range from 50% to 90% of the maximum divided in the next categories:
60-70% of maximum heart rate-weight loss, building endurance
70-80% of maximum heart rate-weight management, improving cardio fitness
80%+ of maximum heart rate-interval workouts
