Answer:
The sentence she should include in her draft to show her reflection about the experience is:
D. I never realized how many people lived and worked in the city of Cairo.
Step-by-step explanation:
Options A through C do not consist of reflections. They are merely stating facts. Option D, however, indicates something Tia realized. She saw something that most likely surprised her or, at least, changed a pre-conception she had before the trip. Now, she reflects on how many people live and work in the city of Cairo. Perhaps she never thought of Egypt as a modern and populous country. Perhaps, in her mind, she only saw the ancient side of it, the one so explored and exploited in movies.