Final answer:
A planetary nebula is an outer shell of gas ejected option (c) from a dying star, expanding and illuminated by the said star’s radiation, forming various beautiful and complex shapes in space.
Step-by-step explanation:
A planetary nebula is generated during the later stages of a star’s life cycle. It is not associated with planets, despite the name. Instead, it is a shell of gas ejected by and expanding away from a hot low-mass star nearing the end of its existence.
The stellar outburst that leads to the creation of a planetary nebula is a relatively gentle event compared to cataclysmic explosions like supernovae. Over time, the star sheds layers that expand outward and are illuminated by the central star's ultraviolet radiation, creating striking visual displays in space, some of which are visible as rings, concentric shells, or even bilateral lobes.
These formations can appear different depending on the viewing angle, adding to the complexity and beauty of these celestial phenomena.