【名词&注释】
买卖合同(sales contract)、不安抗辩权(unsafe right of defense)、先履行抗辩权(the right to implement the demurrer fir ...)、后履行抗辩权(defense of later performance)、同时履行抗辩权(right to defense of simultaneous perfor ...)
[单选题]甲、乙签订一买卖合同,但未约定先后履行顺序。在甲未交货时,乙可能拒绝付款。乙享有的这种权利是
A. 同时履行抗辩权(right to defense of simultaneous perfor)
B. 后履行抗辩权
C. 先履行抗辩权
D. 不安抗辩权