The correct option is C No sooner had he asked a question than he was showered with insults.
If the second event occurs immediately after the first, no sooner...than is used to express such situations. In such a structure, no sooner introduces the event that occurred first. No sooner is followed with the past tense 'had'. Options B is wrong since 'then' is used instead of 'than'. Thus, option C is correct as no sooner is followed by 'had'. 'But' cannot be used with no sooner thus option D is wrong.