A.苛勒 B.托尔曼 C.皮亚杰 D.布鲁纳

A．Only three of the four aspects of internal and external balance can be accommodated simultaneously.
B．Only two of the four aspects of internal and external balance can be accommodated simultaneously.
C．Only one of the four aspects of internal and external balance can be accommodated simultaneously.
D．Only two of the three aspects of internal and external balance can be accommodated simultaneously.