In the following questions, few sentences are given. Choose and mark the sentence which contains no grammatical or contextual error in it. If all the sentences are grammatically and contextually incorrect, mark "All are incorrect" option as the answer choice.

The correct answer is: "Neither the manager nor the employees were informed about the policy change."

Let's analyze each sentence step-by-step to check for grammatical and contextual correctness:

1. "The committee have decided to postponed the meeting until further notice."
This sentence contains a grammatical error. The preposition "to" must be followed by the base form of the verb (infinitive), which is "postpone", not the past participle "postponed". Additionally, "committee" is a collective noun acting as a single entity here, which typically takes the singular verb "has" rather than "have".

2. "Each of the students were expected to submit their assignments before Friday."
This sentence is incorrect. The subject "Each" is singular and must be paired with a singular verb. Therefore, "were expected" should be corrected to "was expected".

3. "Neither the manager nor the employees were informed about the policy change."
This sentence is grammatically correct. Under the rules of subject-verb agreement, when two subjects are connected by "neither... nor", the verb must agree with the subject closest to it. In this case, "the employees" (plural) is closer to the verb, so the plural verb "were" is correct.

4. "The data show that a majority of respondents has agreed with the proposal."
This sentence contains an error. The phrase "a majority of respondents" functions as a plural noun phrase, which requires the plural verb "have" instead of the singular verb "has". It should read "have agreed with the proposal."