The correct answer is C — principal. A surety arrangement involves distinct parties. The principal is the person whose obligation or performance is being guaranteed. In a bail bond transaction, the criminal defendant is the principal because the bond guarantees the defendant's compliance with the conditions of release, particularly appearance before the court when required.

The surety is the party guaranteeing the obligation and potentially becoming liable under the bond when its terms are breached. The obligee is the party in whose favor the obligation runs—typically the court or governmental authority in a bail context. An indemnitor is a person who agrees to reimburse the surety for losses arising from issuance of the bond. “Indemnity” itself refers to the reimbursement obligation or agreement, not the defendant's party designation.

The New York PSI licensing outline identifies the parties to a surety bond as principal, indemnitor for principal, obligee, and surety. It also specifically uses the phrase “Surrender of principal (defendant),” directly confirming that the defendant is the principal in bail-bond terminology.

Understanding these roles is essential because each party has distinct contractual rights, duties, and financial responsibilities.

Therefore, the defendant on a bail bond is the principal, making C correct.