The correct answer is option b. complementary.
If the measure of ∠A is 52°, and the measure of ∠B is 38°, then ∠A and ∠B are supplementary.
Supplementary angles are a pair of angles whose measures add up to 180°. In this case, the measures of ∠A and ∠B add up to 52° + 38° = 90°, which is less than 180°. Therefore, ∠A and ∠B are not supplementary.
Congruent angles have the same measure. Since the measures of ∠A and ∠B are not the same, they are not congruent.
Complementary angles are a pair of angles whose measures add up to 90°. In this case, the measures of ∠A and ∠B add up to 52° + 38° = 90°. Therefore, ∠A and ∠B are complementary.