According to the passage, all of the following are the causes for the population explosion in China except ______.

A．it is difficult to carry out the family-planning policy
B．Chinese population will continue to increase rapidly' in the near future
C．birth-rate decreases but the percentage of old people increases
D．more old people survive in the society

A．Doctors are often in a dilemma as to tell the patient his real condition of health.
B．Doctors' reluctance to tell patient truth has no real support in reality.
C．Doctors' lies are different from that of lawyers and government officials.
D．Doctors and patients hold different views about telling trut