In the 30 years he spent exploring Africa, Livingstone covered over a third of the continent and was known for his attempt to find the source of the Nile River. Which revision gives the sentence proper parallel structure?

Correct the sentence below: the pizza delivery boy was neither early nor late he was right on time. a: correct as it is b: the pizza delivery boy was neither early nor late, he was right on time. c: the pizza delivery boy was neither early nor late; and he was right on time. d: the pizza delivery boy was neither early nor late: he was right on time.