Choose the revision to the sentence that is a correctly punctuated compound sentence. If no change is needed, select
"No correction is necessary."
The house was unattractive, I didn't buy it.
The house was unattractive which is why I didn't buy it.
I didn't buy the house because it was unattractive.
The house was unattractive, so I didn't buy it.
No correction is necessary.