**Core Concept**
The question is related to the legal framework governing the punishment of life convicts, specifically in the context of murder. This involves understanding the concept of "double jeopardy" and the Indian Penal Code (IPC) provisions that dictate the punishment for murder.

**Why the Correct Answer is Right**
In India, the IPC Section 302 prescribes the death penalty or imprisonment for life for murder. However, if a life convict commits murder, the punishment is governed by IPC Section 303, which states that the punishment for murder by a life convict shall be death, or imprisonment for life, and also provides for the additional punishment of imprisonment for a term which shall not be less than 20 years, but which may extend to imprisonment for life.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it does not specify the correct section or provision of the IPC that deals with the punishment for murder by a life convict.
* **Option B:** This option is incorrect because it does not accurately reflect the punishment prescribed by IPC Section 303.
* **Option C:** This option is incorrect because it is not a correct section or provision of the IPC that deals with the punishment for murder by a life convict.

**Clinical Pearl / High-Yield Fact**
It is essential to note that IPC Section 302 and Section 303 are distinct provisions that govern the punishment for murder and murder by a life convict, respectively. Understanding the nuances of these provisions is crucial for medical professionals who may be called upon to provide expert testimony in court cases.

**Correct Answer: D. IPC Section 303**