To determine the author's purpose in writing the passage, it would be helpful to look at the content of the passage itself. If the passage focuses on vivid descriptions of a scenic drive, option A might be appropriate. If it focuses on the unique features and experiences of visiting a desert, option B might be the purpose. If the passage provides guidelines on desert living, option C would be correct. Lastly, if the text mainly discusses the characteristics and significance of saguaro cacti, then option D is the right answer.
Without the passage for reference, I can't definitively choose the correct answer, but you can analyze the content of the passage to see which option best reflects its main focus and intent.