How would you release the hydraulic oil pressure before disconnecting the supply piping from the tractor’s attachment or additional equipment?

1. A There are specific drainage taps for this purpose. They should be opened for a few seconds.
2. B Move the operation lever in all directions when the engine is off.
3. C Turn off the engine, wait a few minutes and only then disconnect the piping.
4. D Connect the pressure discharge passage between the supply line and the return line.