Then you should try a new hobby. There is not a “preponderance of evidence” showing that the professor was wrong. The evidence from demographic studies and census results show that while many families were torn apart by slave auctions; the majority of black families managed somehow to stay together: Anything from 60 to 70% from the sources I am finding, and it varies widely from area to area and period to period.
The evidence all seems to suggest though, that the professor was correct; Answer C would also have been correct, but answer C does not contradict answer D. They are both correct.
The real irony here is that a higher percentage of black Americans seem to have been raised in two parent homes (such as they were) during slavery, than today. That is a pretty shocking indictment of modern culture when you think about it.