Answer:B. An activity that makes him lose track of time.
Explanation: your well-being involve being mental fit, physical fit and being on the right track with your daily activity as a result .
An activity that takes all your time doing just one thing may not be a health activity because you still have to maintain a balance between your daily routines.
You can't devote all your time to one thing because in the process you may forget other activities that are so important to maintain your overall well-being .