In the Parable of the Persistent Widow (Luke 18:1-8), what theological principle does Jesus emphasize through the widow's unwavering appeals to the unjust judge?

A God will always grant immediate relief to those who suffer injustice, rewarding their faith with tangible blessings. B The effectiveness of prayer depends on the persistence and volume of requests made to God. C Believers should maintain unwavering faith and prayer, even when answers seem delayed, trusting in God's ultimate justice and timing. D God is indifferent to the plight of the oppressed and requires constant nagging to be moved to action.