Choose the option that correctly completes the sentence: 'Neither the manager nor the employees ___ aware of the policy change until Monday.'

With 'neither...nor,' the verb agrees with the noun closer to it — 'employees' is plural, so the verb should be 'were.'

Choose the option that correctly completes the sentence: 'Each of the students must submit ___ essay by Friday.'

'Each' is singular, so the pronoun referring back to it must also be singular: 'his or her,' not the plural 'their.'

Choose the option that correctly completes the sentence: 'By the time the last guest arrived, the caterers ___ already packed up the food.'

The sentence describes an action completed before another past action ('arrived'), which requires the past perfect tense: 'had already packed.'

Choose the option that correctly completes the sentence: 'Each of the committee members ___ scheduled for review next week.'

The subject of this sentence is singular ("each," "one," "every one," or the noun closer to the verb in a "neither...nor" construction), so the verb must also be singular: 'was.'

The stack of documents on the archivist's desk ______ waiting to be catalogued for weeks.

Which choice completes the text so that it conforms to the conventions of Standard English?

The subject is 'The stack' (singular); 'of documents' is a prepositional phrase that does not control the verb. The singular 'has been' agrees. The plural forms wrongly agree with 'documents.'