The correct answer is A.
A counterclaim would refute, or argue against, the original statement. The original argument said that high-sugar foods should be considered as harmful as alcohol and tobacco.
Therefore, a counterclaim should provide the opposite view: that high-sugar foods are NOT as harmful as alcohol and tobacco. For this reason, answers B, C, and D can be eliminated, as they further argue that high-sugar foods are harmful and easily obtained.
The only answer that provides a true counterclaim to the original argument is A, because it argues that high-sugar food cannot be as harmful as alcohol and tobacco because it provies a nutrient the body uses for energy.