Which of the following terms describes the action of telling an attorney during a deposition?

The term that accurately describes the action of telling an attorney during a deposition is "testimony." In the context of legal proceedings, testimony refers to the statements made by a witness under oath, which can occur during a deposition or in court. During a deposition, witnesses provide sworn statements that are recorded and can later be used in trial.

While deposition refers specifically to the out-of-court process where testimony is collected, testimony encompasses the content of what is being said by the deponent. Cross-examination is related to questioning a witness after their initial testimony, typically in a trial setting. Interrogation generally refers to the questioning of a suspect or witness, often by law enforcement, which is not relevant in this context. Therefore, "testimony" is indeed the most fitting term for the actions occurring during a deposition scenario.