[单选题]
Which of the following is a 8v;fqk) s ksag bp.5.el/ad y.false statex uzxx )b4q,xo38pte 4ment?
A. All points on a given wave front have the same phase.
B. Rays are always perpendicular to wave fronts.
C. All wave fronts have the same amplitude.
D. The spacing between adjacent wave fronts is one-half wavelength.