For Which of the Following Reasons Does Frost Typically Form

Multiple Choice

For which of the following reasons does frost typically form on the inside of a windowpane rather than on the outside?

A) The inside of the pane is colder than the outside.
B) There is less water vapour touching the inside of the pane.
C) There is more water vapour touching the inside of the pane.
D) The inside of the pane is just as warm as the outside.