Answer:
a. True
Step-by-step 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 <em>one and only one</em> 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.