Which body's primary responsibility is investment and asset management for the government?

The Department of Investment and Public Asset Management (DIPAM) is the correct choice as it is primarily responsible for managing government investments and assets. DIPAM plays a critical role in the government's financial strategy by overseeing the disinvestment process and managing public sector undertakings. This includes activities like optimizing the returns from government assets, implementing policies related to investment, and enhancing the overall efficiency of government investments.

The other entities listed do not center their responsibilities around investment and asset management for the government. The Department of Economic Affairs typically focuses on the economic policy-making aspect, while the Department of Revenue deals with tax collection and fiscal administration. The Ministry of Home Affairs is responsible for internal security and national integration, making its functions distinct from investment management. Hence, DIPAM's specific mandate aligns directly with the question's focus on investment and asset management.