Answer:
<em>C. the nation, and since then,</em>
Exclamation: If you're joining two sentences together you need a comma to do so. By placing a comma after "nation" and "then" you are making a run-on sentence.
Answer:
The Hadleys were thrilled to purchase their Happylife Home and were proud to provide their children with the high-tech nursery, a "miracle of efficiency selling for an absurdly low price." The nursery gives the children hours of entertainment, and the house itself performs all the chores that would otherwise occupy George and Lydia's time. There is no need for a routine, since all the cooking and cleaning are silently taken care of by the house, and there is no need for much personal interaction, either. Even...
