Directions: Supply suitable auxiliaries/idioms/phrases for the question.

The appointment with the doctor _________ be as early as next week.

Here, might is the correct option, as it is used to indicate the possibility that something is true or will happen in the future. Must is a modal verb indicating that somebody is compelled to do something because of a rule or law, or that is necessary or advisable to do something. Will is used to indicate future time, polite questions or requests, etc. Would is used to express the sense of will in reported speech or when referring to an event that has not happened yet.