I can't see the answers clearly, but I can see the question. So, I'll just give you a clue/hint.
A stars brightness actually depends on how far it is from your location. If it's far away, it will be dimmer than its counterpart that is closer. To summarize it, if two stars have the same brightness level and one is farther away than the other, the one farther away will appear dimmer than its closer counterpart.
Answer: Last option (total energy always remains constant)
Explanation:
The Law of Conservation basically states that energy cannot be created or destroyed. Only changed from one form to another (potential, kinetic, chemical, etc.) so it makes sense that the net energy is unchanging.
Heat energy can be transferred from a source to a receiver by conduction, convection and radiation.