**Core Concept**
Colposcopy is a diagnostic procedure used to examine the cervix, vagina, and vulva for precancerous lesions or cancer. CIN-III (Cervical Intraepithelial Neoplasia grade 3) is a high-grade lesion that can potentially progress to invasive cancer if left untreated.

**Why the Correct Answer is Right**
The next line of management for a CIN-III lesion is **conization** (biopsy of the cervix). This involves removing a cone-shaped sample of tissue from the cervix to confirm the diagnosis and rule out invasive cancer. Conization is necessary because CIN-III lesions are at high risk of progressing to invasive cancer. The procedure helps to determine the extent of the lesion and guide further treatment.

**Why Each Wrong Option is Incorrect**
* **Option A:** **Hysterectomy** is not the immediate next step for a CIN-III lesion. While it may be considered for women who are postmenopausal or have completed childbearing, it is not the initial management strategy.
* **Option B:** **Loop electrosurgical excision procedure (LEEP)** is a type of biopsy that can be used to treat CIN-III lesions, but it is not the preferred next step. LEEP is typically used for smaller lesions or as a diagnostic tool.
* **Option D:** **Pap smear follow-up** is not adequate for a CIN-III lesion. A Pap smear is a screening test, not a diagnostic tool, and it may not accurately reflect the extent of the lesion.

**Clinical Pearl / High-Yield Fact**
For high-grade cervical lesions, conization is essential to determine the extent of the lesion and guide further treatment. This can involve more aggressive treatments, such as hysterectomy, if the lesion is invasive.

**Correct Answer:** C. Conization of the cervix.