After the Parkfield programme, experts concluded that earthquake prediction in terms of days and years was

A．Scientists will be fully prepared with equipment to collect more information if an earthquake occurs.
B．It enabled scientists to predict an impending earthquake on time scales of hours to days.
C．A moderate earthquake did occur in the region sometime between 1985 and 1993 just as predicted.
D．People in the Parkfield region were less panic but more prepared for any coming earthquakes.

A．has remained unchanged all these years.
B．has undergone drastic changes.
C．has become the capital of Black America.
D．has remained a symbol of the dangers of inner-city life.