Filial piety, the respect that a child shows to his or her parents, was practiced under Confucianism Taoism Legalism the Mandate of Heaven

The answer is Confucianism. Confucius expressed reverence to the parents, elders, and ancestors as VERY important. According to him, the parent to child relationship is the most important one, for a peaceful society depends good filial piety.

the answer you are searching for is A, Confucianism