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37. B          38. a or c not sure.         39. A.          40. c

Explanation:

The etching is an intaglio strategy for printmaking. A corrosive safe ground is applied to the outside of a plate, which is then drawn into, uncovering the metal plate underneath. The plate is then submerged in corrosive, which nibbles the open zones into the plate. Tone and surface can likewise be added to the plate.
The most punctual, known marked, and Urs Graf delivered dated carving in 1513. This was engraved onto a steel plate with one load of line