the correct year option is not listed in your multiple choice answers. It’s about 3-4year that is why they give you 4 years green card extension notice. however, it may move a little quicker it you file your N-400. I know this is not what you expected to here but don’t worry am in the same boat with you. let keep hope alive together.

2years+

it's definitely any 3 years or more! you'd be lucky if you get approved in two years