Final answer:
a. Around age 2
A naming explosion occurs in children around age 2, which is a period of significant vocabulary increase and the development of simple sentence structures.
Step-by-step explanation:
The naming explosion typically occurs in children around age 2. This is a period when toddlers experience a significant increase in their vocabulary. During this stage of development, children ages 0 to 2.5 are learning many new words and begin to put together words in simple sentences. The leap in language acquisition is so dramatic that it is referred to as the 'naming explosion.' It is part of the cognitive milestones that children reach as they develop the ability to think, problem-solve, and communicate. Therefore, the correct answer to the question 'When does a naming explosion occur in children?' is a. Around age 2.