How are complementary angles characterized?

Complementary angles are specifically defined as two angles whose measures add up to exactly 90 degrees. This key characteristic allows for the identification and classification of pairs of angles, making option B the correct choice. For instance, if one angle measures 30 degrees, its complementary angle would measure 60 degrees, since 30 + 60 = 90.

Understanding this definition is fundamental in geometry, especially when working with right angles and various geometric shapes. Other options may include angles that measure different sums or play different roles in geometry but do not accurately reflect the definition of complementary angles.