**Core Concept**
The examination of an arrested person by a medical practitioner, as requested by the arrested individual, is a critical aspect of forensic medicine and criminal law. This procedure is mandated to ensure the arrested person's rights are respected and their health is safeguarded during the arrest and detention process.

**Why the Correct Answer is Right**
Section 54 of the Code of Criminal Procedure (CrPC) specifically addresses the medical examination of an arrested person at their request. This provision acknowledges the arrested individual's right to seek medical attention, even if they have not been formally charged or imprisoned. The medical practitioner's role in this scenario is to conduct a thorough examination, document findings, and provide a report that may be used as evidence in court. This examination is essential for ensuring the arrested person's health and well-being, as well as for gathering crucial information that may aid in the investigation.

**Why Each Wrong Option is Incorrect**
**Option A:** Section 53 of the CrPC deals with the examination of an arrested person by a medical practitioner at the request of the police, not the arrested person. This is a different scenario, and the medical examination is conducted for the purpose of gathering evidence, rather than solely to ensure the arrested person's health.

**Option C:** Section 56 of the CrPC pertains to the examination of an accused person by a medical practitioner in cases where the accused is mentally unstable or incapacitated. While this section does involve medical examination, it is not directly related to the examination of an arrested person at their request.

**Option D:** Section 57 of the CrPC is not directly related to the medical examination of an arrested person. This section deals with the general powers of police officers, and while it may touch on aspects of police procedure, it does not specifically address the medical examination of an arrested individual.

**Clinical Pearl / High-Yield Fact**
It is essential for medical practitioners to be aware of their role in the criminal justice system, particularly with regards to the examination of arrested individuals. By understanding the relevant sections of the CrPC, medical practitioners can ensure they are providing high-quality care while also respecting the rights of the arrested person.

✓ Correct Answer: B. Section 54