Sentences of a paragraph are given below in jumbled order. Arrange the sentences in the right order to form a meaningful and coherent paragraph.

A. It is more a matter of a person's attitude to life.

B. Optimism is not a complicated philosophy or school of thought.

C. While an optimist always looks at things with hope, a pessimist sees the dark and bad side of things.

D. Such a person takes a bright and positive view of life.