Please choose the correct ending to complete the given sentence: Computers and Electronics: [header] How to deactivate a net10 phone [title] Consume all your remaining airtime balance. [step] It would be best to make the most out of the service while you can, so use any airtime you still have on your net10 phone. Make calls or send out text messages until your balance reaches zero.

Ending1: [title] Do not top-up your net10 number. [step] Your account will automatically deactivate if it doesn't have any airtime left at the end of the current month. Ending2: Talk to your doctor and ask about taking this route, as it may help to self-deactivate your net10 by making a withdrawal. [title] Always recall the three key steps when you receive a message from your carrier. Ending3: [substeps] Expending all your airtime might make the phone soon run out of power (the device won't power on if you turn it off during most calls). A flat breakfast can make the most of your extra 15 minutes. Ending4: [substeps] If you're calling or texting before 9, save this time for calls when you're doing an activity outside of your work. [title] Attempt to save your phone from possible activation surges.

Answer format: ending1/ending2/ending3/ending4