The（①） program means a program written in a high-level language.It is generally translated to an（②）program,which is in a form directly understandable by the computer.The translation is usually done by program called （③）. 

The（） program means a program written in a high-level language.It is generally translated to an（）program,which is in a form directly understandable by the computer.The translation is usually done by program called （）.

A．compiler

B．assembler

C．compile

D．transfer