This question consists of a sentence which is divided into four parts numbered (1) to (4). Only one part of the sentence is not acceptable in standard written English. Identify that part which contains an error.

Correct option is B

The error lies in (b) will have left their fields.
Explanation: The sentence contains a mismatch in the tenses used for the conditional clause. The phrase "if they had known" is in the past perfect tense, which requires the main clause to be in the past conditional (e.g., "would have left") instead of "will have left" (future perfect).
Correct Sentence: "The farmers would have left their fields if they had known that a thunderstorm was approaching."
Grammatical Rule: In third conditional sentences (used for unreal or hypothetical situations in the past), the structure is:
· If-clause (past perfect tense) + main clause (would have + past participle).
Explanation in Hindi: वाक्य में "will have left" का प्रयोग गलत है क्योंकि यह future perfect tense दर्शाता है। जब "if they had known" जैसा past perfect tense का प्रयोग होता है, तो मुख्य वाक्य में "would have + verb" का प्रयोग होना चाहिए।
सही वाक्य: "The farmers would have left their fields if they had known that a thunderstorm was approaching." (किसान अपने खेत छोड़ देते अगर उन्हें पता होता कि तूफान आ रहा है।)