The obligations of U.S. citizenship include the following:
- Defend the nation - This is an obligation, as citizens may be called to serve in the military or may be required to register for the draft.
- Obey laws - Citizens are required to follow all local, state, and federal laws.
- Pay taxes - Citizens are obligated to pay taxes to support government services.
- Serve on juries - Citizens may be required to serve on juries when summoned.
"Vote in all elections" is not an obligation; while voting is an important civic duty, citizens are not legally required to vote in every election.
Therefore, the correct obligations of U.S. citizenship from your list are:
- Defend the nation
- Obey laws
- Pay taxes
- Serve on juries