In each of the following questions, four sentences have been given containing errors. Find out which of the following sentences, if any , is error-free. If all the given sentences have errors, then choose “ All are incorrect”.

The correct error-free sentence is: "The swearing-in of Droupadi Murmu as the 15th President of India is a truly momentous event."

Let us analyze each sentence step-by-step to identify the grammatically correct option:

1. "A special economic zone will offers Indian companies the opportunity to set up a range of industries"
Error: The modal verb "will" is followed by the third-person singular verb "offers".
Correction: Modal auxiliary verbs (will, shall, can, could, would, should, etc.) must always be followed by the base form of the verb. Thus, "will offers" should be corrected to "will offer".

2. "The monsoon would dampen coal production, pressuring generators to importing more coal."
Error: The infinitive structure is used incorrectly as "to importing".
Correction: The infinitive marker "to" is followed by the base form of the verb, forming "to + V1". Therefore, "to importing" should be corrected to "to import".

3. "The swearing-in of Droupadi Murmu as the 15th President of India is a truly momentous event."
Analysis: This sentence maintains correct subject-verb agreement (singular subject "swearing-in" agrees with singular verb "is"), proper preposition usage, correct noun forms, and appropriate adjective/adverb placement ("truly momentous event"). Therefore, it contains no grammatical errors.

4. "Indigenous organizations has urged the government to probe the schools and expedite measures for reconciliation."
Error: Subject-verb agreement conflict.
Correction: The subject "Indigenous organizations" is plural, so it requires the plural auxiliary verb "have" instead of the singular "has". The sentence should read "Indigenous organizations have urged...".

Thus, the third sentence is the only error-free statement.