What Is Important to Do When Drawing a Histogram

What is important to do when drawing a histogram?

A) Use no more than four class intervals, except for categorical variables.
B) Leave gaps between the bars so the reader can easily distinguish between the class intervals.
C) Label the vertical axis, so the reader can determine the counts or percent in each class interval.
D) Make certain the mean and median are contained in the same class interval, so the correct type of skewness can be identified.