The correct answer is A. Assimilation
Step-by-step explanation:
In child development, assimilation refers to a complex mental process in which new information such as events, objects, people, etc. is integrated into existing knowledge or the information children already know. This implies reinterpretation and including new information in existing concepts or categories. This process occurs in Sarah as when she sees the flute she categorizes it as a type of whistle which shows that she includes new information into categories and ideas she already knew.