**Core Concept**
The management of postmenopausal bleeding involves a thorough evaluation to rule out malignancy, particularly endometrial cancer. This is because the risk of endometrial cancer increases with age, and postmenopausal bleeding is a common presenting symptom.

**Why the Correct Answer is Right**
The next step in management would be to perform an endometrial sampling or biopsy to obtain a tissue diagnosis. This is because postmenopausal bleeding can be caused by a variety of factors, including atrophy, polyps, and cancer. An endometrial biopsy allows for the evaluation of the endometrium for abnormal cell growth, which is crucial in the diagnosis and management of endometrial cancer. The biopsy can be performed using a Pipelle or a vacuum-assisted device.

**Why Each Wrong Option is Incorrect**
**Option A:** Performing a pelvic ultrasound would be a useful adjunct to the physical examination, but it is not the next step in management. While an ultrasound may provide information about the endometrial thickness and the presence of any masses, it does not provide a definitive diagnosis.
**Option B:** A Pap smear is not relevant in the evaluation of postmenopausal bleeding, as it is used to screen for cervical cancer. Postmenopausal bleeding is a symptom that requires further evaluation of the endometrium.
**Option C:** A pelvic examination is an essential part of the evaluation of postmenopausal bleeding, as it allows for the assessment of the cervix, uterus, and adnexa. However, it is not the next step in management, which involves obtaining a tissue diagnosis.

**Clinical Pearl / High-Yield Fact**
Postmenopausal bleeding is a red flag symptom that requires urgent evaluation and management. Delaying the evaluation can lead to a poor outcome, as endometrial cancer can progress rapidly.

**Correct Answer: D. Endometrial biopsy**