What happens to a star approaching a black hole in a binary system towards the end of its life cycle?

As a star approaches a black hole in a binary system toward the end of its life cycle, it undergoes significant changes due to the immense gravitational pull of the black hole. When a star swells into a red giant, it expands dramatically, and its outer layers may become loosely bound. As it gets closer to the black hole, the gravitational forces at play can lead to the star being gradually pulled apart and its material being consumed by the black hole. This process is known as tidal disruption, where the star's matter forms an accretion disk around the black hole before ultimately falling in.

This choice accurately reflects the astrophysical processes that occur during such encounters. The other options do not accurately capture what happens: stars do not simply vanish without a trace nor remain unaffected; nor do they instantaneously become black holes themselves without specific conditions being met. Thus, the behavior of the star as it transforms into a red giant and interacts with the black hole provides the correct context for understanding this phenomenon in astrophysics.