A student has the concept of fraction. He/she can easily understand the concept of rational number, by linking it with fraction. According to Piaget which cognitive process is responsible for this ?

Correct option is B

Assimilation is the process of incorporating new information into an existing schema. According to Piaget, assimilation is the primary cognitive process responsible for learning. In the case of the student who can easily understand the concept of rational number by linking it with fraction, assimilation is at work. The student is able to understand the concept of rational number because they are able to assimilate it into their existing schema of fraction.
Scaffolding, decomposition, and decentration are all cognitive processes that can also play a role in learning. However, assimilation is the most important cognitive process for understanding new concepts.