Could someone walk me through how to do this?

First of all if you didn't know, all triangles should add up to 180 degrees. We know either A or B is correct. 90 + 60 = 150. 180 - 150 = 30 degrees
30 + 90 + 60 = 180 degrees so it is correct BUT.. 90 + 30 = 120, so 180 - 120 = 60 degrees. 90 + 30 + 60 = 180. So they are both in fact, correct.

If there is only one answer, it will be (B) because its the same triangle just flipped around.

Idk idk idk idk idk idk idk idk