What is the ruling if a person confesses (*iqrār*) to having guaranteed another under the condition of having an option (*khiyar*)?

Primary text

If a person confesses that he entered into a surety contract stipulating an option, the surety obligation remains binding upon him, and the condition becomes void. This is because his confession affirmed the principal obligation, and subsequently, the condition which nullifies that obligation is invalidated, resembling the act of excepting the entirety of a matter.