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. Pick from: 1. There is not enough light being reflected off the person in the room. 2. Light rays cannot pass through a window twice. 3. Outside light does not pass through windows. 4. Sunlight is not as intense as other sources of light.
The answer is: