What can we say about a polarizing filter with vertically aligned chemical molecules?

A.
It will allow vertically polarized light to pass through it.
B.
It will allow horizontally polarized light to pass through it.
C.
It will block unpolarized light.
D.
It will allow all light to pass through it unchanged.

Ascientist notices that an oil slick floating on water when viewed from above has many different colors reflecting off the surface, making it look rainbow-like (an effect known as iridescence). she aims a spectrometer at a particular spot and measures the wavelength to be 750 nm (in air). the index of refraction of water is 1.3