Best Answer - Chosen by Voting
'Invented' is the correct answer. Because we are talking about something done in the past we need to use past tense, which is 'invented'.
'Invents' is in present tense, which is something someone is doing now, not something they have done before. Edison invented the electric light many years ago: he isn't inventing it right now, so we use past tense.
I hope that's not confusing!