What is the fate of a star that is over 3 times the size of our sun?

A star that is over three times the size of our sun follows a distinct path in its life cycle, primarily driven by its mass. Once such a massive star exhausts its nuclear fuel, it undergoes a supernova explosion. This explosive death is the result of the gravitational collapse of its core, leading to the formation of either a neutron star or a black hole, depending on the remaining mass after the supernova.

In the case of stars greater than approximately 3 solar masses, the resultant core after the supernova can be so dense that it collapses entirely under its own gravity, forming a black hole. This is a region of spacetime exhibiting such strong gravitational effects that nothing—not even light—can escape from it. The formation of a black hole represents the ultimate fate for such massive stars, making it the correct answer for this question.

Conversely, options like becoming a red giant or a white dwarf typically pertain to stars with lower mass. Red giants are often the result of stars similar to the sun expanding and cooling as they enter the next stage of stellar evolution. White dwarfs are remnants of lower-mass stars that have shed their outer layers after exhausting nuclear fuel, which does not apply to extremely massive stars.