Which sentence does not contain any punctuation errors? A. Traffic was heavy, consequently we were late. B. Traffic was heavy consequently, we were late. C. Traffic was heavy; consequently we were late. D. Traffic was heavy; consequently, we were late.
D.
The two parts are independent of each other, which dictates the use of a semicolon. "Traffic was heavy." and "We were late."
"Consequently" is a transition between the two, and requires a comma.