Final answer:
The most important virtue a ruler can possess according to Confucianism is benevolence, as it underpins other virtues and emphasizes empathy and a shared humanity.
Step-by-step explanation:
According to Confucianism, the most important virtue a ruler can possess is benevolence (option D). Confucius placed a high priority on the rulers exemplifying virtuous leadership, highlighting the relational and community-driven nature of Confucian ethics. Underlying the Confucian virtues is the principle of benevolence, represented by the concept of ren, which suggests a shared humanity and empathy towards others.
While filial piety is crucial, expressing loyalty and respect within the family unit, it supports the larger virtue of benevolence in relations outside of the family as well. Wisdom, humility, and other virtues all branch from the essential root of benevolence, guiding leaders to act with a sense of generosity and empathy towards their subjects.