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: Dental
A 45 year old farmer has itchy erythematous papular lesions on face, neck, 'V' area of chest, dorsum of hands and forearms for 3 years. The lesions are more severe in summers and improve by 75% in winters. The most appropriate test to diagnose the condition would be – 
Select and explain. 
A. Skin biopsy, B. Estimation of IgE levels in blood, C. Patch test, D. Intradermal prick test
C: Patch test
Answer: C: Patch test 
Explanation: This patient has :-

Itchy papular lesions on face, neck, V shaped area of chest, dorsum of hand.
Exacerbation in summer and improvement in winter.

Both of these are clinical clues for the diagnosis of photodermatoses.
"Photopatch test is used to confirm the diagnosis of photoallergic dermatosis".