'If he didn't get a flat tyre' is second conditional. This imagines a hypothetical present or unlikely future. The situation described is a hypothetical past so third conditional is needed. B or D would work.

A is grammatically the wrong tense, as others have noted. You could hear native speakers say that, though, because it is common to simplify the tense when there is no ambiguity. And D does have the correct tense but isn’t the most natural. We’re more likely to say that we ‘get’ flat tires than ‘have’ them, though both are correct.

"A" is wrong because "did not" is simple past (combined with the infinitive "get"). The required tense is past perfect: "had not gotten". The correct answer is D which uses past perfect: "he had not had". The inversion that replaces "he had not had" with "had he not had" is a common one when using subjunctive mood, of which this sentence is a good example.