Answer:
C .) 83 °
Explanation:
Angle b and 99° are on straight line so it's supplementary angles and we know that sum of all angles of supplementary angles is 180 °.
➛ b + 97 ° = 180 °.
subtract each side by 97 °
➛ b + 97° - 97° = 180° - 97°
➛ b = 83°