## Core Concept
The patient's presentation of multiple, small hypopigmented macules on the upper chest and back, arranged around follicles, with fine scaling on the surface, is suggestive of a superficial fungal infection. This condition often presents with lesions that can coalesce to form larger patches. The fact that the patient had similar lesions a year ago which subsided with treatment hints at a recurring condition.

## Why the Correct Answer is Right
The clinical presentation described is classic for **pityriasis versicolor**, a superficial fungal infection caused by *Malassezia* species. These organisms are part of the normal skin flora but can cause disease under certain conditions. The fine scaling on the surface of the macules and their arrangement around follicles are particularly indicative of this condition. A **potassium hydroxide (KOH) preparation** is a simple and effective test to confirm the diagnosis. When a skin scraping from the lesion is treated with KOH, the characteristic **spore and hyphae** ("spaghetti and meatballs") appearance under the microscope confirms the presence of *Malassezia*.

## Why Each Wrong Option is Incorrect
- **Option A:** This option is blank and cannot be evaluated.
- **Option B:** This option is blank and cannot be evaluated.
- **Option C:** This option is blank and cannot be evaluated.
- **Option D:** This option is blank and cannot be evaluated.

## Clinical Pearl / High-Yield Fact
A key clinical pearl for pityriasis versicolor is that it often presents with **hypopigmented or hyperpigmented macules** and can be more noticeable after tanning, as the affected areas do not tan properly. The condition is also known for its **recurrence**, which aligns with the patient's history of similar lesions a year ago.

## Correct Answer Line
**Correct Answer: B. Potassium hydroxide (KOH) preparation**.