**Core Concept**
The most common presentation of extra-pulmonary tuberculosis (TB) is a manifestation of the disease affecting organs and tissues outside the lungs, typically involving the lymphatic system, bones, joints, and genitourinary tract. This extrapulmonary form of TB often presents with non-specific symptoms, making diagnosis challenging.

**Why the Correct Answer is Right**
The correct answer is lymphadenitis, which is the inflammation of lymph nodes, usually as a result of the spread of Mycobacterium tuberculosis from the lungs or other infected sites. This condition often presents with painless, enlarged lymph nodes in the neck, armpits, or groin area. The lymph nodes may be tender to the touch and can be associated with systemic symptoms such as fever, weight loss, and fatigue. Lymphadenitis is the most common form of extrapulmonary TB and is often the first sign of the disease.

**Why Each Wrong Option is Incorrect**
**Option A:** Lymphadenitis is not the same as lymphoma, which is a type of cancer that arises from the immune cells. While both conditions can cause lymph node enlargement, they have distinct clinical and pathological characteristics.

**Option B:** Genitourinary TB is a type of extrapulmonary TB that affects the kidneys, bladder, or reproductive organs, but it is not the most common presentation. Genitourinary TB often presents with symptoms such as hematuria, dysuria, or infertility.

**Option C:** Meningitis is a type of extrapulmonary TB that affects the central nervous system, but it is relatively rare. Meningitis caused by TB can present with symptoms such as headache, fever, and stiff neck.

**Clinical Pearl / High-Yield Fact**
The most common site for lymphadenitis in extrapulmonary TB is the cervical lymph nodes, and the disease often presents with bilateral involvement. This is a key clinical feature that can help differentiate TB lymphadenitis from other causes of lymphadenopathy.

**Correct Answer:** C. Meningitis