Which of the following is correctly punctuated?
A. Brian looked at me for a long time before saying, "If that is what you want, I will do it."
B. Brian looked at me for a long time before saying. "If that is what you want, I will do it.”
C. Brian looked at me for a long time, "before saying if that is what you want, I will do it."
D. Brian looked at me for a long time before saying, "if that is what you want, I will do it."