Answer:
a. True
Explanation:
The frequency distribution is a summary of the gathered data set, in which the interval of values is divided into classes.
A requirement for a frequency distribution is for the classes to be mutually exclusive and exhaustive. That is, each individual, object, or measurement in the data set must belong to one and only one class.
Then, we can conclude that each individual, object, or measurement must appear in at least one (in fact, only in one) category or class.