Herald spots are seen in:

 # Herald spot is seen in:

A. Psoriasis

B. Erythema multiforme

C. Pityriasis rosea

D. Pemphigus 

The correct answer is C. Pityriasis rosea.

Pityriasis rosea is a common benign papulosquamous disease causing acute skin eruption of unknown etiology, often considered to be a viral exanthema. 

It is characterised by the appearance of superficial light red macules or papules, either generalised over most of the skin surface or localised to thighs, trunk, axillae or groin.

The individual exanthematous lesions are ovoid, with long axis parallel to the natural lines of cleavage of the skin, covered by thin, silvery scale. The generalised outbreak is preceded by primary lesion or herald spot, 7-10 days previously, that appears as bright red spot, 3-4 cm in diameter.