Hello, please consider the following.

Let me know if you need further explanation.
Thank you
Answer:
C
Step-by-step explanation:
y=1/x, the reciprocal is the same. Reciprocal would be reflected across y=x
2. Angle Addition Postulate as they are adding both angles
3. 60 + 40 = m <ABC because it's a substitution
4. 100 = m <ABC as it is simplified already
5. Definition of obtuse angle
I’m not hundred percent sure must I believe it’s 0