Which of the following was considered most important by ancient greek philosophers such as plato and aristotle?

You didn't provide choices, but let me suggest an  PURSUING WISDOM

In addition to Plato and Aristotle, there were many other Greek philosophers, and their ideas were not all in agreement with each other.  But in general, the Greek philosophers all agreed that pursuing wisdom is the most important thing in life.  One of the earliest of Greek philosophers, Pythagoras (in the 6th century BC), is thought to have coined the term "philosopher."  The report is that Pythagoras did not want to claim to be a wise man who already had great wisdom, but that he was a "lover of wisdom" who sought to be wise.  In Greek, "philos" is a word for "love" and "sophia" is the word for wisdom.  So a "philosopher" is a "lover of wisdom."

The great philosopher Socrates (5th century BC) was famous for saying, "The unexamined life is not worth living."  He saw the goal of his life as constantly seeking wisdom -- and that what truly made him wise was recognizing how little he truly knew with certainty.  Plato was a student of Socrates and learned to do the same sort of deep examination of life.  Aristotle was a student in Plato's school, and carried on the tradition of deep thinking.

Plato and Aristotle had many ideas which were very different from one another.  They did not agree on all the details of how the universe is constituted or how best to arrange one's life or society.  But they did both  seek wisdom as the most important thing in life, as did other philosophers before and after them.

stick up my a**