The doorknocker is an important object, though. The doorknocker showed Scrooge Jacob Marley's face, in which led him through the events of the "night before Christmas" Without have seeing Jacob Marley's face he wouldn't have had any motivation.
It’s the third answer, pretty sure :)
I'd personally go with the 2nd option, but don't count on it so quickly yet.
Carelessly/ careless / carelessness
