The correct answer is A. Blaschkitis. 

Blaschkitis is a rare inflammatory dermatosis best characterized as an ezcematous papular or vesicular eruption that follows multiple lines of Blaschko. Adults are most commonly affected and it can have a relapsing-remitting course with spontaneous resolution within days. While histologically it appears as a spongtiotic dermatitis it is clinically thought to be a varian of lichen striatus.

Linear Psoriasis: is a variant of plaque psoriasis that is often seen due to Koebner phenomenon. Clinically best characterized as thick, silvery scaly plaques. It does not follow a dermatomal or blaschkoid pattern.

Herpes simplex is a viral derived cutaneous illness best described as painful, pruritic vesicles that usually do not follow a dermatomal or blasckoid pattern. Herpes zoster does follow a dermatomal pattern.

Factitial dermatosis is best described as jagged edged erosions and superficial ulcers in various stages of healing. Sites most affected are reachable for the patient such as the upper extremities, upper back, hands, scalp, face and neck.

Linear lichen planus clinical presentation includes polygonal violaceous-red plaques on the extremities (most often). They tend to come up in sites of previous trauma (Koebner Phenomenon). Does not follow dermatomal or blaschkoid pattern.

References: Bolognia J, Cerroni L, Schaffer JV. Dermatology. Philadelphia: Elsevier; 2018. Chapter 62.