The answer is b.gold can’t really explain but the answer is b.
Answer - Inter-molecular attractions
Explanation-
As we know everything around us is made up of matter that means everything has molecules as their basic structure. The state of anything is decided by the spaces between the molecules.
The state of the objects that have strong inter-molecular attractions a solid and gradually the lesser will be in state of liquid and gas. The attraction between the molecules is overcome only when a certain amount of energy is provided from outside.
As the size of a star increases, luminosity increases. If you think about it, a larger star has more surface area. That increased surface area allows more light and energy to be given off. Temperature also affects a star's luminosity.