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:
I’m sure Luisa was very disappointed when she failed the exam
A. Luisa must be very disappointed when she failed the exam.
B. Luisa must have been very disappointed when she failed the exam
C. Luisa may be very disappointed when she failed the exam
D. Luisa could have been very disappointed when she failed the exam