Which ancient Indian ruler's governance was characterized by a strongly centralized administrative framework?

The correct option is Chandragupta Maurya.

Step-by-Step Explanation:

1. Historical Context:
Chandragupta Maurya was the founder of the Mauryan Empire in ancient India (reigned c. 321–297 BCE). With the help of his chief advisor, Chanakya (also known as Kautilya), he established one of the largest and most powerful empires in South Asian history.

2. Administrative Framework:
The governance under Chandragupta Maurya is renowned for its highly organized, highly centralized administrative system, detailed in Kautilya's famous treatise, the Arthashastra, and corroborated by the accounts of Megasthenes (the Greek ambassador to his court).

3. Key Features of Mauryan Centralization:
- King at the Apex: The ruler held supreme executive, judicial, and legislative authority.
- Elaborate Bureaucracy: A well-defined hierarchy of ministers, superintendents (Adhyakshas), and officials managed trade, agriculture, taxation, and law and order.
- Secret Service Network: An extensive network of spies ensured security, intelligence gathering, and central control across provinces.
- Standardized Taxation & Standing Army: A centralized revenue system funded a massive standing army directly controlled by the throne.

4. Comparison with Other Options:
- Samudragupta: Ruled during the Gupta Empire, which relied more on decentralized, feudatory administrative practices.
- Harshavardhana: Ruled in the 7th century CE with a feudal structure where regional lords held significant autonomy.
- Pulakeshin II: A famous Chalukya ruler of southern India whose empire was also organized largely around regional vassals.

Therefore, Chandragupta Maurya's reign is specifically recognized for founding a strongly centralized imperial administrative structure.