From Each of the Following Descriptions of Bullet Holes, Estimate

From each of the following descriptions of bullet holes, estimate the distance from the shooter to the target.
a. A few widely scattered gunpowder particles with no soot around the entrance hole
b. A dark ring around the bullet hole, but no soot or gunpowder particles
c. A halo of soot surrounding the entrance hole along with scattered specks of powder grains
d. Scorch marks and melted fibers surrounding the entrance hole