Which completes the syllogism?



If the time is between 9:00 AM and 5:00 PM, then the post office is open.
If the post office is open, then people may buy stamps or mail packages.
Therefore, if …




a. people may buy stamps or mail packages, then they can also send express mail too.


b. the post office is open, then it is Friday.


c. the time is between 9:00 AM and 5:00 PM, then many people are likely at work and unable buy stamps or mail packages.


d. the time is between 9:00 AM and 5:00 PM, then people may buy stamps or mail packages.