Answer:
a. granted to the national government by the U.S. Constitution
Step-by-step explanation:
Expressed powers
The expressed power or the enumerated power or delegated powers , are listed in the Article l of section 8 in the constitution of the united states .
The expressed powers that is listed in the Article one , include the exclusive federal powers and the concurrent powers which are shared with the states , all the powers are contrasted with reserved powers which only the state have .
Hence , according to the question , the correct option is a .