Answer: it allows people to publicly voice their opinions. It plays an important role in positively influencing government policies.
I think it’s C but don’t trust me on my word
They wanted to present them as if they were gods. This was quite common in history and is a reason for example why pharaohs got pyramids built in their honor. The giant heads depicted their leaders as gods or someone who is in general larger than life itself. It was a sign of respect and others who would visit would also see this and know who they are dealing with. Such heads can still be found and examined which is important when trying to understand their ancient culture.