Final answer:
The correct answer is both option a and b. Martin Luther King Jr. effectively uses quotes from religious texts and appeals to moral authority in his 'Letter from Birmingham Jail' to persuade white religious leaders and others to support the civil rights movement. He strongly invites the church to embody its moral responsibilities.
Step-by-step explanation:
Martin Luther King Jr. utilizes his deep personal connection to the church in "Letter from Birmingham Jail" in two prominent ways: by quoting religious texts to support his arguments (a), and by appealing to the moral authority of the church (b). These strategies help him to confront and persuade his audience, which included white religious leaders and a broader national readership.
King's quotations from religious texts underscore the moral imperative of his civil rights advocacy, invoking shared values to justify his calls for immediate action. Additionally, he explicitly challenges the church's leaders "In the midst of a mighty struggle to rid our nation of racial and economic injustice, I have heard so many ministers say, 'Those are social issues with which the Gospel has no real concern,'" thus criticizing their reluctance to address the societal issues at hand.
By doing this, he holds the church accountable for failing to uphold social justice, highlighting the disconnect between religious teachings and actions, and urging them to recognize civil rights as a moral and spiritual mandate.