The strange, otherworldly incidents of pilgrim's progress are an allegory of the struggles that people may undergo in achieving religious faith. how does the use of allegory john bunyan convey his message that faith is the key to salvation? a.)in allegory, each symbol has a clear meaning, so allegory convince readers that bunyan 's ideas are true. b.)the use of concrete characters and events to stand for abstract concepts readers understand bunyan's themes. c.)by tracing christian's allegorical path to the celestial city, readers can track their own progress toward their goals. d.)because the allegory is also an adventure story, readers can enjoy it even if they don't share bunyan 's religious beliefs.