【名词&注释】
行为人(actor)、违法行为(illegal activities)、不安抗辩权(unsafe right of defense)、民事行为(civil act)、履行合同(perform a contract)、先履行抗辩权(the right to implement the demurrer fir ...)、婚姻登记(marriage registration)、后履行抗辩权(defense of later performance)、同时履行抗辩权(right to defense of simultaneous perfor ...)、符合规定(conforming to prescribed)
[单选题]一方在对方履行债务不符合约定时,有权拒绝其相应得履行要求,这是()。
A. 先履行抗辩权
B. 不安抗辩权
C. 同时履行抗辩权(right to defense of simultaneous perfor)
D. 后履行抗辩权(defense of later performance)