Bob will not develop a good habit if
a. works out for only one week
b. develops a consistent schedule of exercise
c. works out with a friend
d. uses success strategies

A.works out for only one week

Explanation:

Making a habit of exercising is often one of the most difficult steps. The laziness of the early days, or the early weeks, can make us unable to create a sport-related habit and abandon the idea ahead of time. For this habit to be created it is necessary that the individual exercises constantly several times during the month. For that reason we can say Bob will not develop a good habit if he works out for only one week.