A search is defined as:

A search is defined specifically as an examination for evidence related to criminal activity. This definition encompasses the legal parameters of what constitutes a search under the Fourth Amendment, which protects individuals from unreasonable searches and seizures. In this context, a search typically refers to a law enforcement officer's action of looking for physical evidence that may relate to a crime, such as illegal substances, weapons, or stolen property.

The other options, while they are activities that may occur in the context of law enforcement, do not fit the precise legal definition of a search. Investigating a person's background can involve looking into their history or conduct, but it does not necessarily involve searching for physical evidence on that person or at a location related to a specific crime. Reviewing surveillance footage is a form of information gathering but does not constitute a search in the legal sense, as it is often conducted without physically entering a property. Similarly, questioning by law enforcement pertains to interrogation rather than the act of searching for tangible evidence. In summary, option B accurately reflects the legal definition of a search, making it the correct choice.