Step 1: Define "Ghost Print." A ghost print is a second, much fainter impression pulled from a printing plate without re-applying ink. The ink remaining on the plate after the first print creates a pale, ethereal "ghost" of the original image.
Step 2: Relate the concept to the options. This technique is a defining characteristic of Monoprint (and Monotype). In monoprinting, the artist works on a non-porous plate, and the first pull removes most of the ink. The residual ink is just enough to create the secondary ghost image, which is valued for its unique, subtle qualities. This is not a standard feature of the other listed techniques.