An example of a power reserved exclusively for the States is the power to A. establish health standards. B. enforce laws. C. build infrastructure. D. conduct elections.

The power reserved exclusively for the States, as indicated by the options provided, is the power to conduct elections. Therefore, the correct answer is D. conduct elections. This authority is explicitly granted to the individual states under the U.S. Constitution, emphasizing the decentralized nature of the electoral process in the United States.