How does the Parable of the Two Sons (Matthew 21:28-32) challenge the religious leaders' understanding of obedience and righteousness?

A It demonstrates that outward conformity to religious laws is the ultimate measure of righteousness. B It suggests that only those born into religious families are capable of true obedience. C It reveals that true obedience is demonstrated by a change of heart and action, regardless of initial resistance. D It implies that both initial obedience and later repentance are equally acceptable in God's eyes.