A negative sentence has a negative word like 'no', 'not', 'never' or 'without' before the verb. Alternately, it has a negative noun like 'nobody' or 'nothing'. As the meaning has to remain unchanged, we must remember to modify the verb or the object, which has a meaning opposite to the verb in the original sentence.
Option A is incorrect as it does not have a negative word. It is an affirmative sentence.
Option B: This is a negative sentence because it has the word 'not' in it. The opposite of the phrase 'lived a short life' is "did not live a long life'. Hence, this sentence conveys the same meaning as the original sentence and this option is correct.
Option C is incorrect as it has no negative word and it is an affirmative sentence. Further, the meaning of this sentence is different from the original sentence.
Option D is incorrect as option A is the correct answer.