You did not include options in your question, but based on the meaning of the word cryptic, your answer will be 'A HIDDEN MEANING'.
When you say that something is cryptic, it means that, that thing has a meaning that is mysterious or obscure.
From the way the word was used in the given sentence, it means that the message the teacher was passing across about the test is hidden, it was not understood by any of the students.
The correct answer to this open question is the following.
There is no question here. It is just a statement.
Furthermore, you did not specify if this statement belongs to a novel, a play, a movie, or what?
It is so difficult to help you without the question and the proper references.
However, trying to help you, we can infer that you are talking about the ghost in the play "Hamlet," written by English author William Shakespeare.
Being that the case, yes, the appearance of the ghost helps create an eerie mood and grabs the audience's attention. Shakespeare, being the expert writer he was, knew how to create suspense in the readers. As the ghost does not speak, this adds mystery and suspense to people's minds. The audience would probably want to know more about the ghost in the king's clothes and ist purpose to appear. Most people could think that the ghost is there because it has issues to resolve.
Explanation:
this is the correct answer
The sharks fin scared the people at the beach