Step 1: Understanding the Concept:
The question asks to identify the names of the buildings that constituted the great library of the ancient Nālandā Mahāvihāra (University).
Step 2: Detailed Explanation:
The library of Nālandā was known as the Dharma Gunj (Mountain of Truth). According to historical accounts, particularly from Tibetan sources like the writings of Taranatha, it was a vast repository of knowledge housed in three magnificent multi-storied buildings. The names of these three buildings were:
Ratnasāgara (Ocean of Jewels)
Ratnodadhi (Sea of Jewels)
Ratnarañjaka (Jewel-adorned)
These buildings correspond to options (B), (D), and (C) respectively.
Let's evaluate option (A) Ratnakirti. Ratnakīrti was a renowned Buddhist philosopher and logician, primarily associated with the Vikramaśīla University, not a building at Nālandā.
Step 3: Final Answer:
The correct names for the Nālandā library buildings are Ratnasāgara, Ratnarañjaka, and Ratnodadhi. Therefore, the option that includes (B), (C), and (D) only is the correct one.