Light Has a Wavelength of 600 Nm in a Vacuum

Multiple Choice

Light has a wavelength of 600 nm in a vacuum.It passes into glass,which has an index of refraction of 1.50.What is the wavelength of the light in the glass?

A) 600 nm
B) 500 nm
C) 400 nm
D) 300 nm
E) 900 nm