On a Tzanck smear, the presence of acantholytic cells with characteristic multinucleated giant cells most classically suggests infection with which virus (when herpes simplex virus is not among the listed choices)?

A positive Tzanck smear (showing multinucleated giant acantholytic keratinocytes) is classic for the herpesvirus family — herpes simplex virus and varicella-zoster virus both produce this pattern, and pemphigus vulgaris produces acantholysis without the multinucleation. When HSV is excluded as an answer choice, VZV is the next best herpesvirus-family answer.