Answer : Option D) He should start walking two miles a day, three days a week. After two weeks, he will jog one mile and walk one mile three days a week.
Explanation : As TJ wants to increase his cardiovascular fitness level then he needs to start off with walking for at least two miles per day for 3 days in a week.
Once he is regular with this regime, he can push little harder and raise his activity level a bit by starting to jog for a mile and walking another mile for three days in a week.
This will increase the activity of heart and fresh oxygen will be breathed in by lungs. More energy will be produced and heart will be more active.