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."You're a Grand Old Flag' has such an upbeat melody," John observed.
 C."I've always loved the patriotic song 'You're a Grand Old Flag,'" John said.
 D."Could we perform 'You're a Grand Old Flag at the concert?" John asked.