Which process involves questioning a witness or opposing side in a trial?

The correct answer is the process that specifically refers to the questioning of a witness or the opposing party in a trial known as cross-examination. Cross-examination is a critical part of the courtroom procedure where attorneys challenge the witness's testimony presented during direct examination by the opposing side. This allows for the introduction of doubt or alternative perspectives regarding the witness's statements, promoting a thorough examination of the evidence.

Interrogation usually relates to questioning suspects or individuals outside the courtroom context, primarily used by law enforcement. Questioning, while a general term, does not specifically denote the formal procedures used in a trial setting. Deposing refers to the process of taking sworn testimony from a witness before a trial, typically during the discovery phase, and is not conducted in the courtroom environment like cross-examination. Hence, cross-examination is the term that best describes the specific process within a trial context.