Answer:
3. the more years spent smoking, the less optimistic for success.
Step-by-step explanation:
Smoking is habit and it is generally difficult to quit smoking habit if smoked for quite a number of years. Smoking is considered harmful to health.
A study is done to examined the relationship between the years of smoking and the attitude of the participants asked to quit smoking and rate their optimism on the success of the treatment program.
It is seen that the more numbers of years spend on smoking, it becomes less optimistic for the success of the treatment program.
Thus the answer is
3. the more years spent smoking, the less optimistic for success.