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．illusion
B．imagination
C．presumption
D．fabrication

A．in science, it is not difficult to tell fact from fiction______.
B．the meaning of science is so ambiguous that a few can catch on to its meaning and objectives
C．the fact that scientists ignored the practical side of their discoveries in theoretical research which should be introspected
D．practical-minded people can accurately explain the meaning and objectives of science as a whole