An offer has the binding force upon the offerer within the validity and can be refused by the offeree; in this case, the refusal is called counter-offer and serves as the offer of a new round.

An offer has the binding force upon the offerer within the validity and can be refused by the offeree; in this case, the refusal is called counter-offer and serves as the offer of a new round.

A.报价有约束力的报价人在有效性和可拒绝经受要约人承诺，要约人即受在这种情况下，拒绝被称为还盘，作为新一轮的提供。

B.报价有约束力的报价人具有有效性和可拒绝经受要约人承诺，要约人即受在这种情况下，拒绝被称为还盘，作为新一轮的提供。

C.提供一个有约束力的发盘人有效并可由受要约的拒绝，在这种情况下，拒绝被称为还盘，作为新一轮报价。

D.要约在有效期内对发盘人具有约束力，受约人可以拒绝;在这种情况下，拒绝称为还价，并作为新一轮的要约。

正确答案是D