In legal studies, understanding the authority and power to arrest is crucial. Here are the relevant details regarding who can arrest a person:
1. Magistrate cannot arrest a person: Magistrates have judicial authority but typically do not have the power to execute arrests themselves. They can issue warrants or orders that enable enforcement agencies to make an arrest.
2. Private person cannot arrest a person: Although there are limited circumstances under common law where a private person may perform a "citizen's arrest," it is generally not within the regular rights of a private individual to arrest another person.
3. Police officer can arrest a person: Police officers are empowered by law to arrest individuals. They are tasked with maintaining law and order and have the authority to detain someone suspected of committing a crime.
Based on the above explanations, the correct statement is: Police officer can arrest a person.