I would also say D ( it introduces the speaker's sense of fondness for the orchards) is the answer because the original statement describes being in an orchard as a pleasant experience instead of dull and uninteresting like A would suggest. B would not be the correct answer because of the adjectives used. C would also not be correct because the original statement doesn't describe what the orchard looked like.
The answer should be D, because he says he feels a sense of warmness when he thinks about the orchards. Warmness is describing his emotions about the fondness of the orchard.
