Which of the following is defined as the use of a word too broadly?

The correct answer is A. Overextension.

Explanation: Overextension refers to the phenomenon where a child uses a word in a broader context than its correct meaning. For example, if a child uses the word “dog” to refer to all four-legged animals, that is an instance of overextension. This reflects a natural part of language development as children learn to categorize and identify objects and concepts.