Which of the Following Is a Correct Exercise Prescription for a 90-Year-Old

Which of the following is a correct exercise prescription for a 90-year-old individual beginning an exercise program?

A) frequency of 2 to 3 days per week, intensity of 40% to 60% of heart rate reserve, duration of 20 minutes
B) frequency of 2 to 3 days per week, intensity of 60% to 80% of heart rate reserve, duration of 45 minutes
C) frequency of 1 day per week, intensity of 40% to 60% of heart rate reserve, duration of 20 minutes
D) frequency of 5 days per week, intensity of 60% to 80% of heart rate reserve, duration of 30 minutes