4. The followings are procedures of air running. (1)Set the ENGINE/REMOTE operation selector switch in the ENGINE position. (Alarm panel in engine room) (2)Open the pressure indicator cocks of all the cylinders. (3)Set the start/stop lever in the STOP position. (4)Hold the START switch pressing for 2 to 3 seconds to effect air running. Which one is correct?(A) (1)→(2)→(3)→(4)(B) (1)→(4)→(3)→(2)(C) (4)→(2)→(3)→(1)(D) (4)→(2)→(1)→(3)