Final answer:
Option (A), Psoriasis is the inflammatory skin disease characterized by excessive keratinocyte proliferation, presenting with skin lesions, arthritis, and nail problems.
Step-by-step explanation:
The inflammatory skin disease involving excessive keratinocyte proliferation, which presents with skin lesions, arthritis, and nail problems, is psoriasis. This condition is characterized by patches of thick, red skin with silvery scales commonly found on the elbows, knees, scalp, back, face, palms, and feet. Psoriasis also has an associated condition called psoriatic arthritis, which can cause inflamed joints.