Please choose the correct ending to complete the given sentence: Computers and Electronics: [header] How to install a gps navigation system for your automobile [title] Note that this unit is compatible only for vehicles come with a 12-volt battery and negative grounding. [title] Avoid short circuits in the vehicle electrical system during installation. [step] Be sure to disconnect the negative terminal (-) from the battery before the installation.

Ending1: [title] Secure all wiring with cable clamps or electrical tapes. [step] Do not allow any bare wiring to remain exposed. Ending2: [title] Generally, these devices operate as above, with or without electricity. [title] Connect a copper wire to the wire terminal of the navigation system. Ending3: [title] Check with your vehicle licensing board to determine if the battery can be wired in the vehicle and each has an av battery. [title] Keep the vehicle on a flat surface, preferably on deck. Ending4: [title] This section uses an inputs ion (dc) meter. [step] Carbon ion meter reduces resistance slightly by breaking down the charge in the drive-area.

Answer format: ending1/ending2/ending3/ending4