Which sentence is punctuated correctly?
a. the store had the shirt is several sizes; however, it was only available in a sea-foam green color.
b. all of the chairs in the hallway were moved; but they were moved into the wrong location.
c. i've said all that i have to say to you; unless you want to continue this conversation at a later date.
d. you need to pick up your suitcase and hurry up; or you'll be late for the afternoon train.