I believe that the correct answer is D.) Morning glories and sunflowers are much easier to raise than orchids.
Explanation:
The <em>whole text </em>explains how "Orchids are wonderful flowers for a beginner to raise," as well as how easy they are to take care of. This is the authors <u><em>claim</em></u>. So the fact that <em>morning glories</em> and <em>sunflowers</em> are <u>easier to raise</u> than orchids completely clashes with the <u><em>theme</em></u> the author is trying to portray.
Therefore, the correct answer is D.) Morning glories and sunflowers are much easier to raise than orchids.