What type of shotgun ammunition might contain multiple projectiles or a single projectile known as a slug?

The correct choice is related to the specific type of ammunition utilized in shotguns. Shotshells are designed to be fired from a shotgun and can contain either multiple small projectiles known as shot or a single large projectile called a slug. This flexibility makes shotshells suitable for a variety of hunting and shooting scenarios, including bird hunting where shot is needed, or large game hunting where a slug is more effective due to its greater mass and penetration.

Cartridges are a broader term that refers to ammunition used in rifles and handguns, which typically includes a casing, primer, gunpowder, and bullet. While cartridges can contain bullets that are analogous to the slug in shotshells, they do not encompass the concept of shots containing multiple projectiles.

Bullets specifically refer to the single projectile component found in cartridges, primarily used in rifles and handguns, and do not typically include shots or slugs meant for shotguns.

Rounds is another general term for ammunition but does not specifically define the type used in shotguns as accurately as shotshells do. Thus, within the context of shotgun ammunition, shotshells uniquely represent the versatility of using both multiple projectiles and slugs.