Final answer:
Vetoing a bill sent by Congress is an example of executive power, an authority held by the President to reject legislation and serve as a check on Congressional power. This showcases the U.S. government's system of checks and balances.
Step-by-step explanation:
Vetoing a bill sent by Congress is an example of b) executive power. When a bill is passed by both chambers of Congress, the President of the United States has the authority to veto the bill. This executive action sends the bill back to Congress with a veto message, highlighting the President's reasons for not approving the legislation. Though this is an executive power, it serves as a check on the legislative power of Congress, illustrating the system of checks and balances inherent in the U.S. governmental structure.
The President has several options when presented with a bill: signing it into law, allowing it to become law without a signature after ten days if Congress is in session, vetoing the bill, or performing a pocket veto if Congress adjourns within ten days of sending the bill to the President. Moreover, the President may issue signing statements to express opinions on the constitutionality of a bill's provisions. However, the power of the President to veto a bill can be checked by Congress if they are able to override the veto with a two-thirds supermajority vote.