choose the sentence with the correct use of quotation marks.

a. "sandburg's "chicago" isn't smooth or beautiful," said mr. raymond. "it is active and vigorous--just like the city."
b. "sandburg's chicago isn't smooth or beautiful, said mr. raymond. it is active and vigorous--just like the city."
c. "sandburg's 'chicago' isn't smooth or beautiful," said mr. raymond. "it is active and vigorous--just like the city."