In "Heads-Up" Digitizing

In "heads-up" digitizing,

A) "meta" (or "control") points must be set up at the edges of the map before beginning.
B) digitizing is performed on a computer screen using an image as a backdrop.
C) a mouse is moved across the mesh of a map taped to a digitizing table to capture points.
D) only lines and polygons can be created;points must therefore be created using tabular x/y data.