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 sentence containing no grammatical or contextual error is: "The appellant was granted bail after furnishing the required surety bond."

Step-by-Step Analysis of Each Sentence:

1. "The surgeon insisted the attendants to vacate the hall before the procedure began."
Incorrect. The verb "insist" is followed by the preposition "on" + gerund ("insisted on the attendants vacating...") or a standard subjunctive clause ("insisted that the attendants vacate..."). It does not take an infinitive object ("insisted [someone] to do [something]").

2. "He has been relocated to the southern depot since the strike ended last month."
Incorrect context/tense usage. "Relocated" is a single completed event, not an ongoing action or state. Combining the present perfect passive "has been relocated" with "since [past event]" creates an incorrect tense structure for a one-time event that was completed at a specific point in time.

3. "Neither of the two pilots were available for debriefing after the flight landed."
Incorrect. Subject-verb agreement rule: The subject pronoun "Neither" is singular and requires a singular verb. Therefore, it should be "was" instead of "were" (i.e., "Neither of the two pilots was available...").

4. "The appellant was granted bail after furnishing the required surety bond."
Correct. This sentence is grammatically sound and contextually appropriate. The passive voice structure ("was granted"), preposition usage ("after furnishing"), subject-verb agreement, and vocabulary are all accurate.