Mark the letter A, B, C, or D on your answer sheet to indicate the sentence that best combines each pair of sentences in the following questions.
Mai usually helps her classmates with their studies. Her classmates appreciate her.
A.Mai usually helps her classmates with their studies, for they appreciate her.
B.Mai usually helps her classmates with their studies, so they appreciate her.
C.Mai usually helps her classmates with their studies, but they appreciate her.
D. Mai usually helps her classmates with their studies, or they appreciate her.