In language development, the words and word combinations that children understand :

Correct option is D

In language development, the words and word combinations that children understand are referred to as 'comprehension'. Comprehension involves the mental processing of language and the ability to understand its meaning, which is a crucial aspect of language development in children. Before children can effectively use language in speech (production), they typically develop an understanding of a significant number of words and phrases. This comprehension is fundamental for the further development of language skills, including speaking and writing.