## Core Concept
The question pertains to the legal principle of burden of proof in medical negligence cases, specifically focusing on when the burden of proof shifts to the doctor to prove their innocence.

## Why the Correct Answer is Right
In cases of **res ipsa loquitur**, the burden of proof shifts to the doctor. Res ipsa loquitur is a doctrine that infers negligence from the very nature of an accident or injury in the absence of direct evidence on how any defendant behaved. It essentially means "the thing speaks for itself," implying that the injury could not have occurred without negligence. When this doctrine applies, it is up to the healthcare provider to prove that they were not negligent.

## Why Each Wrong Option is Incorrect
- **Option A:** This option is incorrect because, in general, the burden of proof lies with the patient to prove negligence. However, there are exceptions like res ipsa loquitur.
- **Option B:** This option does not directly relate to a recognized legal principle shifting the burden of proof to the doctor in the context provided.
- **Option C:** While informed consent is a crucial aspect of medical practice, it does not directly pertain to the burden of proof in cases of alleged negligence.

## Clinical Pearl / High-Yield Fact
A key point to remember is that **res ipsa loquitur** can significantly impact the burden of proof in medical malpractice cases. For example, if a patient suffers a surgical injury to a part of the body that was not the site of surgery (e.g., a retained surgical sponge), this doctrine may apply, suggesting negligence on the part of the medical team.

## Correct Answer: D. res ipsa loquitur.