Mark the letter A, B, C or D to indicate the sentence that best combines each pair of sentences in the following questions.
The student next to me kept chewing gum. That bothered me a lot.
A. The student next to me kept chewing gum, that bothered me a lot
B. The student next to me kept chewing gum bothering me a lot
C. The student next to me kept chewing gum, which bothered me a lot
D. The student next to me kept chewing gum bothered me a lot