The correct option is B 532,304
The number, whose sum of digits is a multiple of 9, is divisible by 9.
Let's add the digits of the numbers of each pair.
225,631
225→2+2+5=9
631→6+3+1=9
∴ These pair of numbers are divisible by 9.
531,304
531→5+3+2=10
304→3+0+4=7
∴ These pair of numbers are not divisible by 9.
Similarly, {243,234} and {711,585} are divisible by 9.
∴ The correct option is b.