Identify the sentence that uses correct punctuation.
a. we had to walk, all the way to the train station, the bus doesn't go that far.
b. we had to walk; all the way to the train station, the bus doesn't go that far.
c. we had to walk all the way to the train station; the bus doesn't go that far.
d. we had to walk all the way to the train station, the bus doesn't go that far.