The word optimum in Paragraph 4 is closest in meaning to ______.

A．The importance of management techniques.
B．The complexity of hospital design.
C．Uses of computers in industry.
D．Applications of the systems approach.

A．Parents ought to send their children to college as a duty.
B．Parents should feel guilty if they are unable, for whatever the reason, to send their children to college.
C．If they can't afford, parents should take loans for their children to go to college.
D．Parents must support their children even after their marriage.