The isolation valves are identical and interchangeable with each other and with the APU shutoff valve. ( )
A.The isolation valves are interchangeable with the APU shutoff valve, so the valves should have the same serial number. B.The isolation valves and the APU shutoff valve are identical. C.The isolation valves are identical with each other and with the APU shutoff valve, but you can not change them each other.正确答案B
