Step 1: Understanding the Question
The question asks to identify which of S. R. Ranganathan's Five Laws of Library Science uses the metaphor of a "living organism" to describe a library's nature.
Step 2: Key Formula or Approach
The approach is to recall and understand the meaning of each of the Five Laws of Library Science.
Books are for use.
Every reader his/her book.
Every book its reader.
Save the time of the reader.
The library is a growing organism.
Step 3: Detailed Explanation
The Fifth Law directly states, "The library is a growing organism."
This law implies that a library is not a static entity. It must constantly grow and adapt in terms of its collection, user base, staff, and physical space.
Just like a living being, it undergoes continuous change and development to remain relevant and functional.
Step 4: Final Answer
The law that equates a library's growth to that of a "living organism" is the Fifth Law. Therefore, Option (D) is the correct answer.