Which of the following is classified as a deadly weapon?

A firearm capable of discharging a shot is classified as a deadly weapon because it is designed specifically to inflict lethal harm or cause serious injury. Firearms are inherently dangerous instruments due to their ability to propel projectiles at high velocities, which can lead to life-threatening consequences. The Missouri legal definition of a deadly weapon often includes items that are specifically designed to cause death or serious injury, and firearms fit this classification.

Other items mentioned, such as a baseball bat, frying pan, and plastic knife, may potentially cause harm but are not categorized as deadly weapons in the same way as a firearm. Their classification usually depends on the context in which they are used, and they do not possess the same inherent lethal capability that firearms do.