What are the stages of stellar evolution for a medium-sized star?

The stages of stellar evolution for a medium-sized star, such as our Sun, follow a distinct path that includes several key phases: the main sequence, red giant, planetary nebula, and white dwarf.

During the main sequence phase, a star fuses hydrogen into helium in its core, which is where it spends the majority of its lifespan. Once the hydrogen in the core is exhausted, the star undergoes a transition to the red giant phase. In this phase, the outer layers of the star expand and cool, giving it a reddish appearance. This expansion occurs because, as hydrogen fusion ceases in the core, gravitational forces cause the core to contract, raising its temperature until helium fusion begins.

Once the star has exhausted its nuclear fuel, it will shed its outer layers, resulting in the formation of a planetary nebula. The remaining core, which is hot and dense, becomes a white dwarf. This white dwarf will eventually cool down over billions of years, fading away as it no longer undergoes fusion reactions.

The other choices refer to different kinds of stellar evolution. For example, the first choice includes a supernova and neutron star formation, which pertain to massive stars instead of medium-sized stars. The third option involves a protostar