The best example of a hero´s inner conflict is option C) A prince struggles to decide whether to kill the man who murdered his father.
Inner conflict is a private war within oneself, it´s a debate between the good and evil. It occurs inside the character´s mind. A great example of an inner conflict is given in the Shakespeare´s play Hamlet where in the first part of the story the prince has a conflict of whether believe to the ghost about how the king was murderer and claim vengeance upon his uncle.
I hope that the asnwer is correct and help you.