I believe the correct answer would be "neutron star"
The supergiant stars are considered as the biggest stars in the universe. They can be thousands of times larger than the Sun and can exhibit a mass up to 100 times more. In the case when the supergiants run out of fuel or hydrogen they give rise to a supernova, and then either turn into a black hole or a neutron star.
A neutron star refers to a very dense but little star, comprising neutrons and emerges as the core of the dead supergiant.
A black hole refers to a location in space, more accurately in time-space, which is most generally known for its drastic gravitational influence and for its dark color.
I think it would be a neutron star.
Explanation: Because a neutron star is the smallest i belive. Hope this helps.
When a supergiant runs out of fuel, the object formed is either a black hole or a neutron star.
EXPLANATION:Supergiant are very large stars in the galaxy that end their lives very quickly. When a supergiant star loses its fuel, it blows itself by a supernove explosion. When supernove explosion happens, the supernova outshines other stars in the galaxy and then slowly faded away leaving a dense object called black hole or neutron star. This black hole or neutron star is surrounded by a mass of very hot gas and the elements of the supergiant star get scattered into the space.