The question asks us to identify what is essentially connected to ‘Knowledge’. Let us analyze the given options:
- Library: A library is a place where a collection of resources in various formats is kept for reading or reference. It facilitates access to knowledge but is not fundamentally necessary for the acquisition of knowledge itself.
- School: A school is an institution designed for the teaching of students. It is a structured environment that supports learning; however, it is not the only place where knowledge is acquired.
- Teacher: A teacher is an educator who imparts knowledge and facilitates learning. Although teachers play a significant role in education, knowledge can be gained through self-study and various other means.
- Learning: Learning is the process of acquiring knowledge or skills through experience, study, or teaching. It is directly responsible for the acquisition and enhancement of knowledge, making it a fundamental part of the concept.
Considering the above points, the essential part strongly connected to ‘Knowledge’ is Learning, because knowledge cannot exist or improve without the continual process of learning.
Thus, the correct answer is: Learning.