There is not enough light being reflected off the person in the room. Light rays cannot pass through a window twice. Outside light does not pass through windows. Sunlight is not as intense as other sources of light.
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: A person in a dark room looking through a window can clearly see a person outside in the daylight. But a person outside cannot see the person inside. Why does this happen?
Possibilities:
- There is not enough light being reflected off the person in the room.
- Light rays cannot pass through a window twice.
- Outside light does not pass through windows.
- Sunlight is not as intense as other sources of light.

There is not enough light being reflected off the person in the room.