0 E, because the reading of Freud probably stimulated the speaker's first thoughts about the significance of dreams. It's doubtful that the speaker thought about that topic at all before reading Freud, so it's not likely that "he didn't think dreams were of so much significance". More likely, he had no thoughts or opinions at all on the matter.
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.