This text indicates that the basic component of scientific research is ______.

A．reading in search of intended information only
B．looking for unexpected information only
C．reading to locate texts to be used in teaching
D．reading to set up superior master indexes

A．it saves a lot of time to find information needed
B．it reads more efficiently than a human mind
C．it covers a much wider range of reference
D．it guarantees reading efficiency and validity