**Core Concept**
Tuberculids are skin eruptions that result from an immune response to an internal focus of tuberculosis (TB) infection. They are characterized by the formation of non-caseating epithelioid granulomas in the skin, which are indicative of a cell-mediated immune response against Mycobacterium tuberculosis.

**Why the Correct Answer is Right**
The correct answer is a type of tuberculid that specifically involves the sweat glands and hair follicles. This condition is caused by the migration of immune cells, including T lymphocytes and macrophages, to the skin, where they form non-caseating granulomas. The granulomas in this condition are composed of epithelioid cells, which are modified macrophages that have engulfed the TB bacteria. The involvement of sweat glands and hair follicles is a hallmark of this condition, and it is often accompanied by other skin manifestations such as erythema nodosum.

**Why Each Wrong Option is Incorrect**
**Option A:** Erythema induratum is a type of tuberculid that involves the skin, but it is not specifically characterized by involvement of the sweat glands and hair follicles.
**Option B:** Lichen scrofulosorum is another type of tuberculid, but it typically affects the skin in a more diffuse manner and is not specifically associated with involvement of the sweat glands and hair follicles.
**Option C:** Granuloma annulare is a benign skin condition that can be associated with TB infection, but it is not a tuberculid and does not involve the sweat glands and hair follicles.

**Clinical Pearl / High-Yield Fact**
Tuberculids can be a challenging diagnosis, as they can mimic other skin conditions. However, they are often associated with underlying TB infection, and a high index of suspicion is necessary to make the diagnosis.

**Correct Answer:** B. Lichen scrofulosorum