When we consider the color of light absorbed by a substance, we are referring to the complementary color of the light that is transmitted or reflected by the substance. An aqueous solution of copper(II) sulfate (CuSO₄) appears blue to our eyes. This color results from the absorption of light in the complementary color range.

The visible spectrum of light can be divided into several regions, each corresponding to a different color. The complementary color of blue is orange-red. This means that the aqueous solution of CuSO₄ absorbs light in the orange-red region of the spectrum.

Therefore, the correct answer is:

Option A: orange-red