## Core Concept
The concept of commuting a death sentence refers to the power to change or reduce a death penalty to a less severe punishment, typically to life imprisonment. This authority is usually vested in high-ranking government officials.

## Why the Correct Answer is Right
In many jurisdictions, the **President** or a **Governor** has the constitutional or statutory authority to commute a death sentence. This power allows them to review the case and decide to reduce the sentence if they believe it is warranted. The commutation process involves a thorough review of the case details, including the crime, the trial, and the defendant's background.

## Why Each Wrong Option is Incorrect
- **Option A:** Typically, a **Judge** cannot commute a death sentence as their role is to preside over the trial and sentence the defendant according to the law. Their impartiality and the legal process limit their ability to alter sentences post-trial, except in very specific and rare circumstances.
- **Option B:** A **Magistrate** usually has limited jurisdiction and authority compared to higher court judges, governors, or presidents. Their powers are generally restricted to lesser offenses and cannot extend to commuting death sentences.
- **Option C:** This option might seem plausible because **Attorneys General** or similar high-ranking legal officers can influence legal proceedings. However, they typically do not have the direct authority to commute death sentences.

## Clinical Pearl / High-Yield Fact
A critical point to remember is that the power to commute a death sentence is a form of **executive clemency**, which can include pardons, reprieves, and commutations. This power is significant in the administration of justice as it provides a final review of the death penalty's appropriateness.

## Correct Answer Line
**Correct Answer: D. President.**