Concept:The correlative conjunction pair “No sooner…than” is fixed; using “when” instead of “than” is an error.
Explanation:The sentence begins with “No sooner did I open the door”.
The word “No sooner” requires the conjunction “than” to complete the comparison of two immediate events.
The phrase “when the rain, heavy and stormy, rushed in” incorrectly uses “when”.
The correct pair is “No sooner…than”, not “No sooner…when”.
Therefore, the error lies in part b) “when”.
Replace “when” with “than” to make the sentence grammatically correct.
The corrected sentence reads: “No sooner did I open the door than the rain, heavy and stormy, rushed in making us shiver from head to foot.”
No error is present in parts a) or c).
Answer:B