Can a rose window be considered an artistic expression?

Yes it can.
A rose behind a window can have artistic expression in the way of expressing yourself, how you feel.
A rose behind a window can be considered artistic expression in the way of, expressing how you see someone else
 A rose behind a window can express just how you feel about a rose behind a window lol :)

Yes rose window can be considered an artistic expression

1) d2) a3) false  4) true  5) false