The correct answer is: d) Sculptures and artistic remains.
Nagarjunakonda is an archaeological site in Guntur district of Andhra Pradesh, India. It was a Buddhist university and monastic center from the 3rd century BCE to the 3rd century CE. The site is known for its sculptures and artistic remains, which include a large number of Buddha images, as well as sculptures of other Buddhist deities and figures. The site is also home to a number of inscriptions, which provide valuable information about the history and culture of the region.
The other options are incorrect because:
- Nagarjunakonda is not known for its relics of the Buddha. The site has not yielded any significant Buddhist relics.
- Nagarjunakonda is not known for its elaborate temple complexes. The site has a number of small temples, but they are not particularly elaborate.
- Nagarjunakonda is not known for its fortifications and defense structures. The site does have some fortifications, but they are not particularly impressive.