Select the most more appropriate option to fill in the blank.

If your child has not met the ______________ vaccination requirements, he or she will not be allowed to attend public school.

compulsory

The most appropriate option to fill in the blank is compulsory.

The word "compulsory" means required by law. In this context, it is the most accurate word to describe the vaccination requirements for public school attendance. The vaccination requirements are not optional or a guideline. They are required by law, and children who do not meet the requirements will not be allowed to attend public school.

The other options are not as appropriate.

• Referral means a recommendation or suggestion. It is not the best word to describe the vaccination requirements for public school attendance because it does not capture the mandatory nature of the requirements.
• Guideline means a general rule or principle that provides guidance. It is not the best word to describe the vaccination requirements for public school attendance because it does not capture the mandatory nature of the requirements.
• Optional means that something is not required. It is not the best word to describe the vaccination requirements for public school attendance because the requirements are not optional.