Which of the Following Statements Is True

Which of the following statements is true?

A) A hi sto gram is created by drawing rectangles whose bases correspond to the class intervals, and the area of each rectangle equals the total number of observations in the sample.
B) A histogram can be used for only categorical variables.
C) A histogram is created by drawing rectangles whose bases correspond to the number of observations in each class.
D) A histogram is created by drawing rectangles whose bases correspond to the class intervals, and the area of each rectangle equals the number of observations in that class