Select the most appropriate option for the given blank.
Please _____________ quiet, everyone; the principal will be here anytime.

The correct option to fill in the blank is (d) keep.
Explanation: The verb "keep" is commonly used with "quiet" to form the phrase "keep quiet," meaning to stay silent.
Meanings of other options:
· Make → To create or produce something.
· Set → To place or fix something in a particular position.
· Have → To possess something.
· Keep → To maintain or hold (Correct).