The correct option is B 9
The given numbers are the multiples of 9.
9 x 5 = 45
9 x 6 = 54
9 x 7 = 63
9 x 8 = 72
9 x 9 = 81
9 x 10 = 90
9 x 11 = 99
So, the next numbers will be
9 x 12 = 108
9 x 13 = 117
difference = 117 - 108
= 9
So, the next numbers will also have a difference of 9.