In the question below, four sentences have been given. Out of four sentences, one sentence is error-free. Find out which of the following sentence is error-free. If all the given sentences have errors, then choose option ‘None is correct’ as the answer choice.

Correct option is C

Correct Sentence: (c) Had they adhered strictly to the guidelines, the irregularities would not have occurred.
Explanation:
· This is a correct example of third conditional sentence structure.
· “Had they adhered” is an inverted form of “If they had adhered.”
· Structure: Had + subject + past participle, ... would have + past participle.
Incorrect Sentences:
· (a) ❌ “Insisted to take” is wrong. Correct usage is “insisted on taking.”
· (b) ❌ Subject is “many of whom”, which is plural → should be “have served” not “has served.”
(d) ❌ “The number of applicants” is a singular subject, so the verb should be “does” not “do.”