Please choose the correct ending to complete the given sentence: Cars & Other Vehicles: [header] How to install a car amp [title] Mount your amplifier on a solid surface that will not conduct electricity. [step] In other words, do not mount it on a metal surface. [title] Disconnect the negative battery terminal.

Ending1: [step] Make sure you know how to reactivate your radio before doing this, if your radio has a security system. [title] Pass the power wire through the firewall. Ending2: [title] Turn off the power to your car. [title] Unscrew the connecting conduit. Ending3: [step] Use your hands to turn off the amplifier and remove the battery. Only leave the negative terminal plugged in. Ending4: [step] Stand away from the amplifier, and ensure that it is unplugged. [title] Activate the battery terminal to engage the small fibroperator cable from which the amplifier coil is attached.

Answer format: ending1/ending2/ending3/ending4