答案及解析：[单选题]In any scanning exchange of bubbling ordering, if the last exchange is to swap elements X > Y for

问题：

[单选题]In any scanning exchange of bubbling ordering, if the last exchange is to swap elements X > Y for Y < X, then: 在起泡排序的任何一趟扫描交换过程中，若最后一次交换是将元素X > Y交换为Y < X，则此后：
AX and Y must have been in place X和Y必然都已经就位
BX must be in place while Y is not necessarily X必然就位，而Y未必
CY must be in place while X is not necessarily X未必就位，而Y必然
DNeither X nor Y are necessarily in place X和Y都未必已经就位