Answer:
B 45 degrees
Step-by-step explanation:
if AB and CA are = the M2 = 90 degrees
in an right triangle ware one angle is 90 degrees and one is 45 degrees the outer one will be 45 degrees
the total of the angles in a triangle is 180 degrees so 180 - 90 = 90
90 - 45 = 45
so the remaining angle is 45.
