Answer:
A. Use mutually exclusive classes.
Step-by-step explanation:
From the given frequency distribution:
[tex]\left|\begin{array}{c|c}$Number of Minutes &$Frequency\\-------&------\\$0 to less than 5 &6\\$5 to less than 10& 9\\$8 to less than 13 &14\\$13 to less than 18 &2\end{array}\right|[/tex]
We can see that we have these class interval
The data in these two ranges will overlap and therefore violates the rule of mutual exclusivity.