Which official document is involved in ensuring the accused appears in court?

The correct choice here is the bail bond, which serves the primary function of ensuring that the accused will appear in court as required. A bail bond is a written agreement by which a bail bondsman provides a guarantee to the court that the accused will be present for their court dates in exchange for a monetary fee or collateral. If the accused fails to appear, the court can take action against the bail amount.

In contrast, a warrant is typically an order issued by a judge to law enforcement to arrest an individual due to suspicion of committing a crime. A summons is a document that notifies an individual to appear in court, but it is not necessarily tied to securing the accused’s attendance through financial means. An indictment is a formal charge or accusation of a serious crime, which also does not directly ensure appearance but rather initiates the legal process against the accused. Thus, the bail bond is the document specifically designed to secure the accused's promise to appear in court.