Ans. is 'a' i.e., Type of weapon o The kind of firearm weapon which fired the shot can be determined by -1) Size, shape, composition and primary or secondary marking of bullet.2) Appearance of wound.o Primary markings (class characteristics or bare codes):# These markings result during passage of bullet through barrel and depend on design, dimensions and manufacturing specifications of weapon. So they are most useful in identifying make and model (class) of weapon. Features noted include1) Calibers and type.2) Number and width of lands and grooves.3) Direction and rate of twist of rifling.4) Pitch (angle of spiral) of rifling.o Secondary markings (individual or accidental characteristics/Bullet finger print):# Irregularities on the inner surface of barrel due to accidental manufacturing defects or sticking of particles of prior fired bullets (later is known as metallic fouling) also produce grooving (marking) on surface of bullet. These secondary individual (or accidental) markings are specific for that particular weapon and used to exclude it from all others (bullet fingerpringing). These are more pronounced on lead bullet (which may even sometimes carry weaving pattern of cloth) and jacketed bullet.o The bullet found in body or crime scene is called crime (exhibit) bullet. It is compared under microscope with test bullet fired from suspected weapon. Using same type and brand of ammunition, the suspected weapon is fired into a box filled with cotton waste (bullet traps), a sand bag, bag of rags, oiled saw, dust, blocks of ice, water tank (bullet recovery tank) or against white bloating paper.