The total library fee for a foreign student in his three-year post-graduate program is ______.

A．Space is limited.
B．His editor is prejudiced.
C．The subject is not important.
D．He is entering choppy and dangerous.

A．dropouts are substantially below Ph.D. s in financial attainment
B．the incentive factor is a minor one in regard to pursuing Ph.D. studies
C．the Ph.D．candidate is likely to change his field of specialization if he drops out
D．about one-third of those who start Ph.D．work do not complete the work to earn the degree