Answer A is a bit nasty. I round 5 to the next highest number on the left. That may not be what you have been told to do. Let us round A to 5.7 and see if anything else does this.
B
Answer B rounds to 5.6
C
Answer C rounds to 5.6 as well. 3 is less than 5 so you round down.
D
Answer D rounds to 5.6(.) The zero has no effect on the 6.
Answer
Since there is nothing special about A and nothing else rounds to 5.7, the answer is A. So your rule is when the last number is 5, you round the second last number to one more than it was, regardless of the properties of the second last number.
