Answer:
Mark is in the phase called "Contemplation".
Step-by-step explanation:
The stage of "contemplation" is the second stage of the model of health behavior, at this stage the individual recognizes his behavior that is detrimental to his health and considers abandoning this behavior in the near future (maximum six months). We can say that Mark is at this stage, because he realized that smoking is very bad for his health and will follow medical advice to be able to quit this behavior in three months.