In this task, you're given a story (which contains five sentences only). Your task is to find all the characters which are available in the given story.

Sentence1: Brad was nervous about the test. Sentence2: He hadn't studied a lot. Sentence3: He went to class. Sentence4: Brad took the test. Sentence5: He got a B on the test.

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
Brad