quote the vault wikia

There are now several possible courses of action which will complete the quest:

* Speak to Harkness and convince him that he's an android. There are several options to choose from in the conversation, but only the final two matter. Regardless of the choices made, they will receive A3-21's Plasma Rifle and +200 Karma (unless convinced to go with Zimmer) as a reward.
* If told his secret is safe with the player, Harkness will do nothing. However, he can still be turned into Zimmer or said to be dead with the Android Component if this is chosen.
* If asked what he will do, Harkness will state his intentions to kill Zimmer. The player may ask if he can order them to leave instead by making up several false charges instead of resorting to violence, or request if they can have the honor of killing Zimmer.
* If told that Zimmer is waiting for him, the player can pass a speech check to convince him to go with Zimmer, at which point they must go to Zimmer and tell him about Harkness. Both rewards can be claimed in this fashion, but only the Bad Karma will be earned. Alternatively, a different speech check can be passed to convince him that he should stay, at which point he'll proceed to go kill Zimmer. If neither speech test is chosen or passed, the player can choose to tell Harkness that it is his choice. He will at that point vanish from the city, having fled to escape Zimmer. Zimmer himself will remain in the Science Lab and occasionally complain to the scientists, but will only say "there's nothing more to discuss" if spoken to.
* Tell Dr. Zimmer the android's human name and reveal the code to uncover the buried memories. The player is rewarded with the Wired Reflexes perk and -200 karma. Dr. Zimmer will then walk to Harkness's location and claim the android as his property. Harkness will initially resist until Dr. Zimmer uses an override code to reset Harkness to factory defaults. Dr. Zimmer and Armitage will then leave Rivet City with Harkness in tow.
* If Zimmer and Armitage are killed after Harkness is reset, the android will stand wherever he was for the rest of the game, continuing to ask for parameters if spoken to.
* To get both rewards in another fashion, tell Harkness who he is, for the A3-21's Plasma Rifle and Good Karma, then ask to kill Zimmer. Reveal to Zimmer and tell him the android is Harkness (this gives Bad Karma, but it will balance out with the previous Good Karma boost unless your Karma was already high for the Wired Reflexes perk. At this point, you may either kill Zimmer, or allow him to wipe Harkness' memory.
* Show Dr. Zimmer the android part received from the railroad agent, and inform him that the android is dead. The reward for this is 50 caps and good karma. This can technically be done at any time after receiving the component