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 3 months old infant is having thick scales on scalp with dandruff. Erythmatous scaly lesions on nasolabial folds are also present. Diagnosis is – 
Select and explain. 
A. Atopic dermatitis, B. Seborrhic dermatitis, C. Xerotic eczema, D. Napkin dermatitis
B: Seborrhic dermatitis
Answer: B: Seborrhic dermatitis 
Explanation: Information in this question are :-


3 months old infant
Erythmatous scaly lesions
Thick scales on scalp → Indicates cradle cap
Lesions on nasolabial folds
Dandruff


All these information (in combination) suggest the diagnosis of Infantile seborrheic dermatitis.
Besides seborrheic dermatitis, no other diseases given in options will have scalp lesions and dermatitis.