162. Many countries are increasing their use of natural gas, wind and other forms of ______.

A．energy

B．source

C．power

D．Material

下列4条指令，需要使用DX寄存器的指令有______条。
(1) IN AX，20H
(2) MUL BX
(3) DIV BL
(4) OUT 20H，AL

A．1

B．2

C．3

D．4