Answer:
B.) Complementary
Step-by-step explanation:
A.) A straight angle is an angle that makes a 180° angle, which is wrong.
B.) A complementary pair is two angles who's sum is 90°. Since in the picture, there is a 90° (you can tell by the little square in it's angle) split in two, it is complementary.
C.) Vertical angles are two angles made opposite by two intersecting lines.
D.) Supplementary angles (2) make a total of 180° when they are added together.
