The correct options are
A Class IX has maximum number of cycles.
B The difference between maximum and minimum number of cycles is seven.
D Class VIII has nine cycles.
According to the pictograph,
there are 5 cycles in class VI,
10 cycles in class VII,
9 cycles in class VIII,
12 cycles in class IX,
and 7 cycles in class X.
Thus, the maximum number of cycles is for class IX (which is 12) and the minimum number of cycles is for class VI (which is 5) and thus, their difference is 12 - 7 = 5.