Question: Why is it better to wear a white T-shirt than a dark blue T-shirt in the summer?

What is the correct answer to the question from the following choices?
Pick from:
I. Light-colored clothes let more air in.;
II. Light-colored clothes prevent sweating.;
III. Light-colored clothes are not as heavy as dark-colored clothes.;
IV. Light-colored clothes reflect more sunlight than dark-colored clothes.;
IV.