**Core Concept**
The underlying principle being tested involves the management and potential complications of non-vital teeth, specifically the effects of bleaching on such teeth. Non-vital teeth are those that have undergone root canal treatment or have died due to trauma or decay. **Bleaching** non-vital teeth is a common procedure to improve their appearance, especially when they become discolored.

**Why the Correct Answer is Right**
Since the correct answer choice isn't provided, let's discuss the general concept. Bleaching non-vital teeth can lead to several sequelae, including external root resorption, tooth fracture, or further discoloration if not done properly. The most common issue, however, is likely related to the **cervical resorption** or **external root resorption**, which can occur if the bleaching agent penetrates to the root surface or if the tooth is not properly sealed.

**Why Each Wrong Option is Incorrect**
**Option A:** Without knowing the specific option, we can generally say that if an option suggests no risk or a very rare complication as the most common sequel, it would be incorrect.
**Option B:** Similarly, if this option proposes a benefit rather than a complication, it would not be the correct answer.
**Option C:** This might suggest a rare or unrelated complication, making it an incorrect choice.
**Option D:** Without the specific text, if this option does not align with known complications of bleaching non-vital teeth, it would be incorrect.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that before bleaching non-vital teeth, the tooth should be properly restored and sealed to prevent leakage of the bleaching agent into the periodontal tissues, which can cause **cervical resorption**. Regular follow-up is also crucial to monitor the tooth's condition.

**Correct Answer:** Correct Answer: D. Cervical resorption