**Core Concept**
The underlying principle being tested is the management of teeth in patients undergoing radiotherapy, particularly in the head and neck region. Radiotherapy can lead to **osteonecrosis** and **radiation caries**, making dental management crucial before starting treatment.

**Why the Correct Answer is Right**
The correct answer choice should be related to the reasons for removing a questionable tooth before radiotherapy, which include preventing **osteoradionecrosis**, reducing the risk of **radiation caries**, and avoiding **dental abscesses** that could complicate radiotherapy.

**Why Each Wrong Option is Incorrect**
**Option A:** This choice is incorrect because removing a tooth can prevent infection.
**Option B:** This choice is incorrect as it reduces the risk of osteonecrosis.
**Option C:** This choice is incorrect because it avoids potential abscess formation.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that dental evaluation and necessary interventions, including extractions, should be completed before initiating radiotherapy to minimize complications.

**Correct Answer:** D. Reducing the risk of dental problems during radiotherapy.