The correct option is A width
In a frequency distribution table, the difference between the upper-class limit and the lower class limit is called the width or size of the class interval. For example, each of the groups 20-25, 25-30, 30-35, etc., is called a class interval. Here, in all the class intervals, the difference between the upper class limit and the lower class limit is 5. Therefore, the class width is 5.