The correct answer is: Sun
Step-by-step explanation:
Sun is the only star in our solar system, and planets orbit around it. Our solar system is the part of Milky way (located in one of the outer bands of the Milky way), and the Milky way is the part of the Universe (Universe is made up of billions of galaxies, and Milky way is one of those galaxies). Hence, in the given options, the Sun is the part of all of the other options given.