A. When subrogation results from a person's performance of the obligation of another, that obligation subsists in favor of the person who performed it who may avail himself of the action and security of the original obligee against the obligor, but is extinguished for the original obligee.
B. An original obligee who has been paid only in part may exercise his right for the balance of the debt in preference to the new obligee. This right shall not be waived or altered if the original obligation arose from injuries sustained or loss occasioned by the original obligee as a result of the negligence or intentional conduct of the original obligor.