Choose the one sentence that is punctuated correctly (check for proper use of quotation marks, apostrophes, commas, periods, question marks, and capital letters):
A. There is little doubt explained the professor that we will have to deal with the problem sooner or later.
B. "There is little doubt explained the professor that we will have to deal with the problem sooner or later."
C. "There is little doubt," explained the professor, "That we will have to deal with the problem sooner or later."
D. "There is little doubt," explained the professor, "that we will have to deal with the problem sooner or later."