[单选题]
When a beam of light (wavelength = 590 nm), originally traveling icea j1w5tnx, c1:3mj9raew w vql1 f73n air, ehvtwgb l.4g1: nters a piece of glass (index :bv wtl 41gg.hof refraction 1.50), its frequency
A. increases by a factor of 1.50.
B. is reduced to 2/3 its original value.
C. is unaffected.
D. none of the given answers
