The Correct answer is C. None of the other answers that are up there make sense.
His depth in landscaping and his ability to model forms with color
It depends on what type of report you are writing. If you are writing an argumentative or informative report, it is essential to include facts and evidence to support your topic. In these kinds of papers, you can also use your opinion, but you can only use 3rd person pronouns. Whereas if you were writing a persuasive report, then you would use more of your opinion on the topic you were trying to cover. (All of this comes from my VERY smart Advanced English teacher... so it’s reliable!) Hope it helps!