TASK DEFINITION: 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.
PROBLEM: Sentence1: Mark was a big fan of nature. Sentence2: He decided to bring trees to the city. Sentence3: He would take a truck load of trees down each week. Sentence4: He would then plant the trees in parks. Sentence5: Over time the trees grew and now Mark is happy!

SOLUTION: Mark

PROBLEM: Sentence1: It was Jordan's birthday. Sentence2: His mother was buying him a cake. Sentence3: Jordan's mother bought a strawberry cake. Sentence4: He had wanted a chocolate cake. Sentence5: Jordan had a tantrum about the cake.

SOLUTION: Jordan, Jordan's mother

PROBLEM: Sentence1: Ralph needed a new computer mouse. Sentence2: So he went to the computer store. Sentence3: He found a nice mouse. Sentence4: He bought the nice mouse. Sentence5: Ralph no longer needed a mouse.

SOLUTION:
Ralph