Answer:
B complementary angles
Explanation:
ED is a line.
Angles EAB and DAB are a linear pair, so they are supplementary.
Angle EAB is a right angle, so angle DAB is also a right angle.
The measure of angle DAB is 90 degrees.
The sum of the measures of angles a and b is 90 degrees.
That makes <a and <b complementary angles.