**Core Concept**
Cervical Pap Smear (CPS) is a screening tool used to detect abnormal cell changes in the cervix, which can be a precursor to cervical cancer. In the absence of gross pelvic abnormalities, CPS can help identify high-risk lesions and guide further diagnostic workup.

**Why the Correct Answer is Right**
The correct answer is related to the use of colposcopy, a diagnostic procedure that uses a specialized microscope (colposcope) to examine the cervix for abnormal cell changes. Colposcopy is used in conjunction with CPS to visualize the cervix and identify high-grade lesions, which may not be apparent through a routine Pap smear. This is particularly useful in the absence of gross pelvic abnormalities, where the risk of cervical cancer may still be present.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not directly relate to the diagnosis of cervical lesions in the absence of gross pelvic abnormalities. While ultrasound can be used to evaluate pelvic anatomy, it is not the primary tool for CPS or colposcopy.
**Option B:** This option is incorrect because it is not a direct diagnostic tool for CPS or colposcopy. While histopathology is essential for confirming the diagnosis of cervical lesions, it is not the primary method for initial diagnosis.
**Option C:** This option is incorrect because it is not directly related to the diagnosis of cervical lesions in the absence of gross pelvic abnormalities. While HPV testing can be used to screen for high-risk strains of the virus, it is not a direct diagnostic tool for CPS or colposcopy.

**Clinical Pearl / High-Yield Fact**
In the absence of gross pelvic abnormalities, a negative CPS does not rule out the presence of high-grade lesions. A repeat CPS or colposcopy may be necessary to ensure accurate diagnosis and guide further management.

**Correct Answer:** D. Colposcopy.