Which revision correctly combines these two sentences?
 There was a lot of traffic today. It took an hour to get home.
 A. There was a lot of traffic today and it took an hour to get home. 
 B. There was a lot of traffic today; it took an hour to get home. 
 C. There was a lot of traffic today, it took an hour to get home.
 D. There was a lot of traffic today it took an hour to get home.