Why Are Fringes Not Observed If the Angle of the Wedge

Multiple Choice

Why are fringes not observed if the angle of the wedge of air in the diagram is too large?

A) For a large angle, the small-angle approximation (sin $\theta$ $\approx$ $\theta$ ) is not valid.
B) the light passing through the wedge of air loses its coherence
C) the fringes overlap
D) the fringes are too close together to be seen individually
E) None of these is correct.