The US Local Airport Keeps Track of the Percentage of Flights

Multiple Choice

The US local airport keeps track of the percentage of flights arriving within 15 minutes of their scheduled arrivals.The stem-and-leaf plot of the data for one year is below. $\begin{array} { l l } 76 & 9 \\77 & 114 \\78 & \\79 & 07 \\80 & 88 \\81 & 2 \\82 & 1 \\83 & 88\end{array}$
In developing a histogram of these data,how many classes would be used?

A) 4
B) 5
C) 6
D) 7
E) 8