Light Travels from Outside a Building to Inside Through a Pane

Multiple Choice

Light travels from outside a building to inside through a pane of glass.Which of the following is true regarding the phase change upon reflection in the case?

A) No phase change occurs at either the inside surface or the outside surface of the glass.
B) A 180^o phase change occurs at both the inside surface and the outside surface.
C) A 180^o phase change occurs at the inside surface but not at the outside surface.
D) A 180^o phase change occurs at the outside surface but not at the inside surface.