All of the following can be considered some of the obstacles artificial intelligence can hardly get over EXCEPT ______.

A．thinks that scientists are on the point of achieving artificial intelligence
B．is in the full conviction that scientists have the competence to achieve artificial intelligence
C．remains doubtful of the fact that scientists have found real artificial intelligence
D．predicts with optimism that achieving artificial intelligence is now near at hand

A．The specialists' complaints can by no means be justified and should thus be dismissed.
B．A machine itself cannot be made to think in that it usually follows the procedures set in advance.
C．Humans generally use their wisdom to assess risks, evaluate the outcomes and make a sensible decision.
D．Machines are after all machines and they will never defeat human chess players.