2. which sentence does not contain any punctuation errors?

a.
i will always remember the words he spoke then "the duties of citizens to the state are no less and perhaps greater than the duties of the state to citizens."

b.
i will always remember the words he spoke then: "the duties of citizens to the state are no less and perhaps greater than the duties of the state to citizens."

c.
i will always remember the words he spoke then; "the duties of citizens to the state are no less and perhaps greater than the duties of the state to citizens."

d.
i will always remember the words he spoke then—"the duties of citizens to the state are no less and perhaps greater than the duties of the state to citizens."