Answer:
Sirius
Step-by-step explanation:
Our solar system is the system which is made of Sun (solar) at the centre and the other astral bodies revolving around it.
This model of the solar system is also known as the heliocentric model of the solar system in which the Sun is present at the centre.
Our solar system consists of the Sun, the planets revolving around it with their moons, the asteroids, meteorites etc.
In the given question, Venus is a planet, Sun is the centre of the solar system and the moon revolves around the planet are part of the solar system but Sirus which is the brightest star is not considered a part of the solar system.
Thus, Sirius is the correct answer.