15. If it is snowing, I cannot ride my bike. If it is
dark, I cannot ride my bike.
Based only on the information above, which of
the following must be true?
A. If I cannot ride my bike, then it must be
dark.
B. If I cannot ride my bike, then it must be
snowing.
C. I do not have a headlight on my bike.
D. If I ride my bike, then it is not dark or
snowing.
E. If it is snowing, then it must be dark.