Think of the countless changes in which you yourself have had a part, the whole universe is change, and life itself is but what you deem it. (Unit 4: The Meditations)What does the author imply?

A、The whole world is ever changing and you will never know what will happen.;
B、The whole world is ever changing and you played a very important part in it.;
C、The whole world is ever changing and it is your thinking that makes it good or bad.;
D、The whole world is ever changing and life is meaningless.