Topic: verb (ক্রিয়া),

Best Answer Explained in Below-:

In the given sentence, "The students went to the principal and requested that the examination -- postponed," we are dealing with a specific grammatical structure known as the subjunctive mood. The subjunctive is often used to express wishes, demands, or suggestions, and it requires the base form of the verb rather than a conjugated form.

In this context, the students are making a request regarding the examination. The verb "requested" sets up a situation that requires the use of the subjunctive mood. Thus, we need the base form of the verb "to be," which is "be." Therefore, the correct completion of the sentence is "requested that the examination be postponed."

The other options—"are," "were," and "should be"—do not fit:
- "are" is a present tense form that does not align with the subjunctive mood.
- "were" is past tense and does not properly convey the request.
- "should be" introduces a modal that changes the original meaning and does not align with the structure of a formal request.

Thus, "A) be" is the only grammatically correct option that maintains the intended meaning of the request.