阴天散射光下物体的拍照，黑白照通常是根据物体的（）进行曝光，使用略微不足的曝光方式，并用（）的显影方式进行处理，提高被摄对象的反差。

As a result of the use of the new technology，the production of this product________50 percent.[ ]

A．has risen to  

B．has been raised to

C．has risen by  

D．has been risen by