Final answer:
The appointment book is generally a confidential document but can be subpoenaed by the court, which means its contents may be revealed legally during the legal discovery process.
Step-by-step explanation:
The appointment book is often considered a private document; however, when it is involved in legal proceedings, it can lose that level of privacy. The correct answer to whether an appointment book can be subpoenaed by the court is A) Confidential. While normally treated as confidential in practice, once a subpoena is issued, the appointment book, like other documents, can be compelled to be produced for legal scrutiny in a court of law. This does not mean it becomes a public document, but its contents may be revealed as part of the legal discovery process.