Explanation:

- Option 1: Collection of Evidence

- This is a fundamental aspect of an investigation. Gathering material and information to establish facts in a case is crucial.

- Option 2: Conducted by a Police Officer or a Person Enjoying the Powers of a Police Officer

- Investigations are often conducted by police or individuals with comparable authority, which gives them the power to collect evidence and question suspects.

- Option 3: Authorised by a Magistrate on His Behalf or a Person in Authority

- At times, a magistrate can delegate investigatory powers to a qualified individual or entity, allowing them to conduct a lawful investigation.

- Option 4: All of Them

- All the statements reflect aspects associated with investigations in various legal systems.