**Core Concept**
The doctrine applicable in the scenario of a retained surgical instrument, such as a pair of scissors, during an operation is a legal concept that deals with the responsibility and liability of healthcare providers in the event of a medical error or negligence.

**Why the Correct Answer is Right**
The doctrine of "Res Ipsa Loquitur" comes into play in such situations. This Latin phrase translates to "the thing speaks for itself," implying that certain events are so unusual that they can only occur through the negligence of the defendant (in this case, the healthcare provider). The doctrine is based on the idea that the plaintiff (the patient) does not need to prove negligence, as the circumstances of the injury are so compelling that they suggest negligence on the part of the defendant. In the case of a retained surgical instrument, it is highly unlikely that the instrument would be left inside the patient without some degree of negligence, making Res Ipsa Loquitur a relevant doctrine.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because Res Ipsa Loquitur is a specific doctrine that deals with the consequences of negligence, not the act of negligence itself.

**Option B:** This option is incorrect because it is not a recognized doctrine in medical law.

**Option C:** This option is incorrect because it is a principle of medical ethics, not a legal doctrine.

**Clinical Pearl / High-Yield Fact**
Res Ipsa Loquitur is often referred to as a "presumption of negligence," which means that the court will presume that negligence occurred unless the defendant can provide a reasonable explanation for the injury.

**Correct Answer: C. Res Ipsa Loquitur**