Option (C)
Step-by-step explanation:
From the picture attached,
Two lines are the parallel lines and one line is intersecting these lines at two distinct points.
mβ 3 = β 6 [Alternate interior angles]
Since, angles 2 and 7 are the vertically opposite angles,
mβ 2 = mβ 7 [Alternate exterior angles]
Therefore, angles β 2 and β 7 are the pair of alternate exterior angles.
Option (C) is the answer.