The correct answer is B. Chronic actinic dermatitis.

The thick, infiltrated plaques on sun-exposed areas are typical of the actinic reticuloid variety of CAD.

PMLE (polymorphous light eruption): The most common variety of PMLE presents as crops of 2–5 mm pink or red papules.

Actinic prurigo: Actinic prurigo is an intensely itchy skin condition caused by an abnormal reaction to sunlight. It presents with small, intensely itchy papules on sun-exposed sites.

Drug photosensitivity: Drug-induced photosensitivity occurs when certain photosensitizing medications cause unexpected sunburn or dermatitis (a dry, bumpy or blistering rash) on sun-exposed skin (face, neck, arms, backs of hands, and often lower legs and feet). The rash may or may not be itchy.

Photo allergic contact dermatitis: Photocontact dermatitis is a toxic or allergic reaction that may occur when certain chemicals are applied to the skin and subsequently exposed to the sun.

References:

Paek SY, Lim HW. Chronic actinic dermatitis. Dermatol Clin. 2014;32(3):355-ix. doi:10.1016/j.det.2014.03.007. Roelandts R. Chronic actinic dermatitis. J Am Acad Dermatol. 1993;28(2 Pt 1):240-249. doi:10.1016/0190-9622(93)70034-q