Answer: B, accommodation
Explanation: "Accommodation is a term developed by psychologist Jean Piaget to describe what occurs when new information or experiences cause you to modify your existing schema." (Provided by study.com)
The answer is C, “how to solve the problem?”
Answer:
It's because books give us many education which helps us and also a friend is said a friend when he/her helps us so books are also our friends.
In my view