The correct response is: More sunlight is reflected than transmitted by the white upper surface of clouds.
On cloudy days, especially in summer, the thick clouds can block a significant amount of sunlight from reaching the surface of the Earth. The upper surfaces of these clouds are often white and reflective, which means they reflect sunlight back into the atmosphere rather than allowing it to pass through. This reduces the amount of solar energy that reaches the ground, leading to cooler temperatures compared to clear sunny days.