The Parable of the Persistent Widow (Luke 18:1-8) primarily emphasizes which aspect of prayer, considering the social context of widows in first-century Palestine?

A The importance of praying loudly and publicly to gain attention from God. B The need to offer material gifts alongside prayers to ensure divine favor. C The necessity of unwavering persistence in prayer, even when answers seem delayed, reflecting the widow's vulnerability and lack of social power. D The idea that God only answers prayers when they are repeated multiple times.