The study of this is psychology and you basically just go off of your experience. But, there is not any actual way to read the mind yet discovered by our technology.
The correct answer is C. Voting is a right and a privilege granted to the citizens in a democracy. When the local elections occur, it's the opportunity the citizan has to participate in the political process and express his preference for a representative. Some countries make voting voluntary and in other countries it's compulsory.
C. All the other ones are way off. I was thinking maybe D but it wasnt a law so C for sure