<prompt> A24-year-old man had multiple, small hypopigmented macules on the upper chest and back for the last three months. The macules were circular, arranged around follicles and many had coalesced to form large sheets. The surface of the macules showed fine scaling. He had similar lesions one year age which subsided with treatment. The most appropriate investigation to confirm the diagnosis isPotassium hydroxide preparation of scalesSlit skin smear from discrete maculesTzanck testSkin biopsy of coalesced macules  <response>: Information in this question are :-Adult patient 24 yrsMultiple small hypopigmented maculesOn chest and backMacules had started around follicle and then coalescedFine ScalesRecurrent after treatmentThe clinical diagnosis is P.versicolor which can be confirmed by examination of scales as wet mounts after treatment with 10 KOH. 