Answer: B. 150°
Step-by-step explanation:
The angle is obviously obtuse and is therefore greater than 90°.
This rules out A. and C.
Also, this angle is not 180° because then it would be flat.
This rules out D.
Leaving the correct answer to be B. 150°
The two large triangles can be proven congruent through SSS ASA and SAS, you have all the congruent angles and sides you could ever need to prove the two large triangles congruent in at least 3 ways