I want to know the answer to the following question:
The ancient buddhist site  in the lower Krsna Valley can be traced to at least what century BCE?
All the background I'm provided with is that "" They note that the ancient Buddhist sites in the lower Kṛṣṇa Valley, including Amaravati, Nāgārjunakoṇḍā and Jaggayyapeṭa "can be traced to at least the third century BCE, if not earlier."". Is that enough to answer the question?