16. Which of the following is not a power of the United States Congress?

A. Enforcing immigration laws

B. Levying and collecting taxes

C. Establishing and paying for the armed forces

D. Regulating commerce between the states

The correct option is A.

The United States Congress are given a number of expressed and implied powers but enforcing immigration laws is not one of them. The power given to the congress include: power to levy and collect taxes, power to regulate commerce between states, power to established and pay for armed forces, power to appropriate funds, etc.