Concept:Subject-verb agreement with a plural noun phrase.Explanation:In this sentence, "the rich" means "rich people" and is plural.Therefore, the verb must agree with a plural subject.The correct negative helping verb is "do not," which contracts to "don't.""doesn't" is singular and would only agree with "he," "she," or "it."Answer:"It is sad that the rich don't pity the poor."So the correct option is B. don't.