Which answer choice is the best revision of the nonstandard sentence shown
below?
We coulda, I dunno, gone to
the store before we got home.

A. I dunno, we could've gone to the store.
We could of, I don't know, gone to the store before we got home.
We could have gone to the store before we got home.
I don't know, we could of gone to the store before we got home.