【正确答案】 B

【答案解析】credible：可信的。convincing：可信的。That is the least convincing excuse that you could offer．convincing可替换credible而不改变句子的意思。workable：可行的，行得通的。Your plan is workable。practical：实际的；现实的。He is weak in practical matters．reliable：靠得住的。John is a reliable man．