In the parable of the Prodigal Son (Luke 15:11-32), what does the father's willingness to forgive the younger son primarily illustrate about God's nature?

A God's approval of reckless behavior when followed by repentance. B God's limited forgiveness, contingent upon perfect obedience thereafter. C God's unconditional love and boundless grace, extending to all who turn to Him. D God's preferential treatment of those who have strayed the furthest.