Answer:
D. 68
Explanation:
According to the figure, the minor arc is 112°, so the other part of the circle would be 360° - 112° = 248°, because a circle has 360° as total arc.
Now, when an external angle is formed by two tangents, that angle is defined as the half-difference between the intercepted arcs, which can be expressed as

Therefore, the right answer is D.