The proper title for this passage should be ______.

A．produces more harmful effects than beneficial ones
B．produces no more harmful effects than beneficial ones
C．is no longer unanimously regarded as the science of the future
D．is not worth pursuing persistently

A．the harmful effects of chlorofluorocarbons on the environment
B．the necessity to ensure the environmental compatibility of new chemical substances
C．the economic feasibility of new chemical substances
D．the objective assessment of the progress in Chemistry