Statistics & Probability

A grouped frequency distribution table with classes of equal sizes using 63-72(72 included) as one of the class is constructed for the following data :
30, 32, 45, 54, 74, 78, 108, 112, 66, 76, 88,
40, 14, 20, 15, 35, 44, 66, 75, 84, 95, 96,
102, 110, 88, 74, 112, 14, 34, 44.
The number of classes in the distribution will be :
(A) 9 (B) 10 (C) 11 (D) 12