"Activation Lock for iPhone, iPad, and iPod touch" is a security feature, one aspect of which is deterring re-selling of stolen devices. To learn more click here --> http://support.apple.com/HT201365
If you do not know the required information and you are not the original owner, get the owner of the account to remove the lock or return the device for a refund or recycle it. The device is otherwise useless to you. If the owner is unknown and has not provided contact information as a message showing in the login screen, there is no way to contact the owner unless the person who gave you the device knows them.
Apple can completely reset a device if a person can provide sufficient evidence of valid ownership. https://al-support.apple.com/#/additional-support Apple says, "Proof of ownership documentation is required," but does not state what currently constitutes proof. Prior to this new online service Apple typically required the original receipt issued by an Apple Authorized dealer and documented provenance (so typically it would be the original owner who does this with a receipt in their name, or a descendant with legal proof of ownership). In other words, I very much doubt you can provide sufficient evidence.