The correct answer is: Only argument I is strong.
Argument I is strong because it is based on the evidence that smoking is harmful to health. The statement “Smoking is injurious to health” is a warning that is based on scientific evidence. This warning is intended to make smokers aware of the risks of smoking and to encourage them to quit.
Argument II is weak because it is based on the assumption that smokers enjoy smoking. However, there is no evidence to support this assumption. In fact, many smokers report that they do not enjoy smoking and that they would like to quit.
Therefore, only argument I is strong.