Correct Answer - Option 3 : Both 1 and 2

__Concept:__

**Class Interval:** Consider we have large data \(\rm x_1, x_2, .......,x_n\), while arranging them, they are grouped into different classes to get an idea of the distribution, and the range of such class of data is called the **Class Interval.**

**Calculation:**

In grouped frequency distribution, the range of given class of data is called the class interval.

Class intervals are generally equal in width and are mutually exclusive.

Hence, option (3) is correct.