Which sentence does not contain any punctuation errors?
a.
i thought of you when i read these words of shakespeare “the fool doth think he is wise, but the wise man knows himself to be a fool.”
b.
i thought of you when i read these words of shakespeare; “the fool doth think he is wise, but the wise man knows himself to be a fool.”
c.
i thought of you when i read these words of shakespeare: "the fool doth think he is wise, but the wise man knows himself to be a fool."
d.
i thought of you when i read these words of shakespeare—“the fool doth think he is wise, but the wise man knows himself to be a fool.”