Which sentence does not contain any punctuation errors?

a."is the song "you're a grand old flag" traditionally sung on independence day? " john wondered.

b."i've always loved the patriotic song 'you're a grand old flag,'" john said.

c."could we perform 'you're a grand old flag at the concert? " john asked.

d."you're a grand old flag' has such an upbeat melody," john observed.