I have realized that the past and future are real illusions, that they exist in the present, which is what there is and all there is. What are your thoughts

i think the answer is c

what lesson are you referencing?

wake*

explanation:

  this riddles' answer is library.

  the "leaves" are a reference to the books' pages that the library contains; the branches are a network of libraries that connect multiple libraries' collections, resources, and items in a system of a common database, integrating them; the branches' organization are a useful management tool for coordinating the multiple collections many libraries have.