You do not know the answer to the following multiple choice question and you need to guess. Based only on the Grammatically Correct strategy, which of the following is likely to be the correct answer?

In the play, the main characters:

a$.$ knows a secret that the reader doesn't know.

b$.$ to walk from their home to the tower.

c$.$ are trying to reach their destination.

d$.$ is moving too slowly.

e$.$ achieving the goal.