All of the Following Statements Are True EXCEPT

All of the following statements are true EXCEPT:

A) to quickly evaluate compression, listen during cranking for an even rhythm and then for a smooth idle.
B) an EGR valve is open at idle during normal operation.
C) when an EGR valve is opened by a vacuum pump, the engine should stumble and run roughly.
D) a vacuum gauge is easy to connect and can be used to qualify engine condition.