California Private Investigator Practice Exam 2026 – The All-in-One Guide to Exam Success!

An affidavit is a written declaration made under oath, which is the reason this choice is the correct answer. In legal terms, an affidavit serves as a formal statement that is sworn to be true by the person making it, known as the affiant. This process typically involves signing the document in the presence of a notary public or other authorized official, providing it with legal standing and ensuring its authenticity.

Affidavits are often used as evidence in court and can pertain to a variety of subjects including facts, events, or the personal knowledge of the affiant. Because an affidavit is a written document, it has the advantage of being a permanent record of the individual's testimony that can be referred back to as needed, thus lending it greater weight than a mere verbal statement.

The other choices do not encapsulate the legal significance of an affidavit. A verbal statement of a witness is not documented and cannot be sworn to in a legal context, a non-legal testimony does not carry the same weight as an affidavit, and an informal promise lacks the required formality and legal consequence associated with a sworn statement.