Final Answer:
The condition characterized by yellowish crusty patches on the scalp is typically associated with seborrheic dermatitis, commonly known as dandruff. Option A is the answer.
Step-by-step explanation:
Dandruff: Dandruff is a common scalp condition where skin cells on the scalp flake off, causing itching and the appearance of white or yellowish scales. These scales may accumulate and form crusty patches.
Psoriasis: While psoriasis can affect the scalp and cause red, scaly patches, it often differs from dandruff in appearance and may not present with yellowish crusts.
Ringworm: Ringworm, a fungal infection, can cause circular, scaly lesions on the skin but typically lacks the yellowish crusty appearance associated with the given description.
Eczema: Eczema can affect the scalp, leading to redness, itching, and flaking, but it may not always present with yellowish crusty patches.
Option A is the answer.