Which is a correctly written sentence, not a run-on?
a. The ferry leaves for the island in fifteen minutes; we need to hurry to catch it.
b. The summer concert series in the park starts Thursday we plan on going every week.
c. The train left the station at 3 o'clock it should be arriving in town any minute now.
d. The library has a good selection of books and movies we borrow some every week.