First we make the fractions homonym ( they must have the same denomitator)
0.6 = 6 / 10 7/9
6/10 = 6 * 9 / 10 * 9 = 54 / 90 7/9 = 7 * 10 / 9 * 10 = 70 / 90
The numbers which are between these numbers are ;
55 / 90 , 56 / 90 , 57 / 90 , 58 / 90 , 59 / 90, 60 / 90 , 61 / 90 , 62 / 90 , 63 / 90 , 64 / 90, 67 / 90 , 68 / 90 , 69 / 90
62 / 90 = 62 / 2 / 90 /2 = 31 / 45
So the right answer is B.
Hope that helps :)