The answer is B: The couple looked at the exterior of the house, they noticed; the paint was in disrepair. The comma (,) is used because there is an inversion in the order of the sentence. "They noticed the couple looked at the exterior of the house." The semicolon (;) connects the two independent clauses that are related in meaning but are separated grammatically. In the example A, the semicolon could be replaced by the conjunction and to connect the two sentences.