Please choose the correct ending to complete the given sentence: Computers and Electronics: [header] How to activate 2 step verification in facebook [title] Install the facebook app on on your mobile phone. [step] Facebook uses a code generator tool in the facebook app as a two-factor security system. You'll be prompted to open the facebook app and enter the code from the code generator.

Ending1: You'll be instructed by a screen that asks for your password. [title] Input your password as one of the field boxes. Ending2: [substeps] If you have any questions or are unsure about a time period in which you'd like to activate this code, launch two step authentication using facebook. [title] Tap the app store from your phone. Ending3: [substeps] Facebook users will be required to provide a valid username, password, and password as well as a twitter or instagram id. Information regarding the code generator tool may be asked for via the app's user interface to determine if you've added properly-known usernames and passwords. Ending4: This only happens when you log into facebook on an unknown computer. If you can't use the facebook app or code generator, facebook will send your phone a text message with the code.

Answer format: ending1/ending2/ending3/ending4