In the Parable of the Persistent Widow (Luke 18:1-8), what theological point is Jesus making about prayer and God's character?

A God is reluctant to answer prayers and must be worn down by persistence. B Prayer is only effective if repeated multiple times a day. C God is a just and compassionate judge who will ultimately bring justice to those who cry out to Him, even when it seems delayed. D Widows are more likely to have their prayers answered than other people.