It can be inferred from the passage that a scientist devoted himself to study the nature of the carbon dioxide likely belongs to those dedicated to______.

A．The Essence of Science and Scientists
B．On Distinguishing Fact from Fiction
C．The Definition of Pure Scientists
D．The Classification of Science

A．is not always as practical as applied science
B．necessarily comes after applied science
C．may cause a multitude of immediate result if properly made use of
D．necessarily emerges from applied science