Line or shape?

A) I've come to believe that this is a line over a shape. It is a line that is either starting off thin and gets fatter as it goes, or the opposite, starts off wide and gets thinner. B) This to me also comes as a line. A wavy line that is thinner at both the start and the end, but thicker in middle. It looks to be a chisel tip that is twisted in the middle to create the thicker line. C) This looks like a shape, a rectangle. Or could also be a very thick line. D) And finally this is a shape. It is a soolid object that doesn't let anything in, or anything out.