The correct answer is D. No error.
The sentence “There is no question of my failing in the examination” is grammatically correct. The word “question” is used in the sense of “doubt” or “uncertainty.” The phrase “of my failing” is a prepositional phrase that modifies the noun “question.” The phrase “in the examination” is a prepositional phrase that modifies the verb “failing.”
The sentence is clear and concise, and it conveys the intended meaning. There is no grammatical error in the sentence.