Final answer:
Mencius notably added to and polished the teachings of Confucianism, focusing on the innate goodness of humans and the importance of virtue, thus deeply influencing East Asian culture and philosophy.
Step-by-step explanation:
Mencius had a significant influence on Confucianism by expanding and enriching its philosophical foundations. He believed in the inherent goodness of human beings and their natural inclination towards virtues, which contrasted with other thinkers like Mozi, who challenged the ritualistic and familial aspects of Confucianism. Mencius also preserved the Confucian tradition of ethical governance and the importance of advising rulers honestly for the long-term well-being of the state.
His contributions helped in spreading Confucian ideas and establishing them as a prominent school of thought that had a lasting impact on East Asian societies. Therefore, the correct answer to how Mencius influenced Confucianism is that he added to and polished the teachings of Confucianism after the death of Confucius.