Which Local Government Code was amended under PD 464?

The correct choice is indeed the Local Government Code of 1983, which was amended under Presidential Decree No. 464 (PD 464). This decree played a significant role in reshaping local governance in the Philippines by modifying certain provisions of the earlier Local Government Code. The 1983 Code was foundational in establishing a framework for local government units (LGUs) and PD 464 aimed to enhance the fiscal capabilities and administrative structure of local governments during that period.

While the other codes mentioned—1991, 1978, and 2001—each represent significant developments in local governance, they were established after PD 464 was enacted. A focus on the 1983 code provides insight into the historical context of local government legislation in the Philippines and illustrates how PD 464 aimed to address the governance challenges faced at that time.