Which sentence does not contain any errors in comma usage?
a. there will be performances this evening at 6: 00 7: 00, and 8: 00.
b. look in the library, on the internet, and in recent periodicals.
c. for your biography of a president find out who he was when he was elected, and what he achieved.
d. few people can fly helicopters airplanes, or seaplanes.