对 a=[4,3,1,5,2,4,6]从左到右进行一轮升序冒泡排序后，a中数据是?

A. [3,1,4,2,5,4,6]

B.[3,1,4,2,4,5,6]

C. [6,4,3,1,5,2,4]

D. [4,3,5,2,4,6,1]