Choice "B" is correct. A noncompensated surety will be discharged from liability if the principal debtor and the creditor modify the terms of the contract in any way. A partial surrender of the debtor's collateral is a modification that will release a noncompensated surety from liability.Choice "d" is incorrect. One of the reasons creditors seek sureties is to have someone who can pay the debt if the principal debtor goes bankrupt. Bankruptcy of the principal debtor will not discharge the surety. Choice "a" is incorrect. The creditor becoming incompetent after the debt arose has no bearing on the liability of either the debtor or the surety.Choice "c" is not as good an answer as "B". The principal's duress will discharge the surety's obligation only if the creditor knew about the duress when the creditor accepted the surety.