What is the difference between aeronautics and astronautics?

What is the difference between aeronautics and astronautics?

• A. Aeronautics is flight within Earth's atmosphere; Astronautics is flight beyond Earth’s atmosphere
• B. Astronautics is flight within Earth's atmosphere; Aeronautics is spaceflight
• C. Aeronautics is propulsion research; Astronautics is avionics
• D. Aeronautics is flight over oceans; Astronautics is flight over land

Answer: (C)