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.

[Q]: Sentence1: My science class took a field trip to the bio park today. Sentence2: Only about half of the students were allowed to go on the trip. Sentence3: My best friend Mark got left behind because he failed a math test. Sentence4: That doesn't seem fair to me because he is really good at science. Sentence5: I don't understand why teachers punish students who really try hard.
[A]: Students, I (myself), Teachers, Mark

[Q]: Sentence1: Jeb wanted to make the football team. Sentence2: He practiced every day. Sentence3: He ran as fast as he could. Sentence4: He could catch well. Sentence5: He made the team and was happy!
[A]: Jeb

[Q]: Sentence1: Natalie had auditioned for the lead in the school play. Sentence2: She won the part and was super excited. Sentence3: She rehearsed for weeks and weeks. Sentence4: On opening night, she acted her little heart out. Sentence5: The play was a huge success!
[A]:
Natalie