Which of the Following Results Is Not Possible from a Laboratory

Which of the following results is not possible from a laboratory examination of firearm evidence?

A) Determining how far from the victim the weapon was held.
B) Determining that two or more cartridge cases were fired from the same weapon.
C) Identifying a bullet as having been combined with a particular shell prior to being discharged.
D) Restoring serial numbers ground off the gun.
E) All of the above can be determined from a laboratory examination of firearm evidence.