Which invention of the Tang and Song Dynasty was the most important?

How is an objective summary different from an argumentative essay? o a. a summary should remain neutral, but an argumentative essay should promote a certain viewpoint. o b. a summary should use direct quotations, but an argumentative essay should paraphrase evidence. o c. a summary should include a works-cited list, but an argumentative essay should not cite others' work. o d. a summary should focus on a thesis, but an argumentative essay should address many different topics.