D

Step 1: Understand that stars emit their own light but are extremely far away, making them much dimmer than the sun.
Step 2: During the day, the sun emits a significant amount of light, brightening the sky and creating a blue color due to Rayleigh scattering of sunlight by the atmosphere.
Step 3: This scattered sunlight produces an intense background brightness that overwhelms the faint light coming from stars. Therefore, we cannot see them.
Step 4: The star's brightness is not sufficient to stand out against the scattered sunlight, leading to their invisibility during the day.
Therefore, the correct answer is D: Atmosphere scatters sunlight into a blanket of extreme brightness through which faint stars cannot be visible.