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.