This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Skin
Patch testing is done for : 
Select and explain. 
A. Atopic dermatitis, B. Irritant contact dermatitis, C. Allergic contact dermatitis, D. Discoid eczema
C: Allergic contact dermatitis
Answer: C: Allergic contact dermatitis 
Explanation: C. Allergic contact dermatitis