Which of the following is an example of a concurrent power?

The power to tax is an example of a concurrent power because it is a power that both the federal government and state governments possess. Concurrent powers are those that can be exercised simultaneously by different levels of government. In the case of taxation, both the federal government has the authority to levy taxes on income, property, and sales, while state governments can impose their own taxes to fund services at the state and local levels. This shared responsibility allows for a dual system of taxation that supports various governmental functions at both levels.

In contrast, the other options listed represent powers that are typically exclusive to one level of government. For instance, the power to declare war is primarily a federal power, confined to Congress, reflecting the national interest in defense and military matters. Similarly, the issuance of currency is also granted specifically to the federal government, which maintains national monetary policy through the U.S. Treasury. Conducting foreign relations is exclusively a federal power, managed by the President and the Secretary of State, as it involves diplomacy and international agreements that are under the purview of national governance.