Which of these is a cold weapon?

Among all the weapons listed, only a dagger is a cold weapon.

A cold weapon (or white arm) is a weapon that does not involve fire or explosions (such as the act of combustion) as a result from the use of gunpowder or other explosive materials. Ranged weapons that do not include gunpowder or explosive materials and melee weapons are cold weapons. Firearms and explosives (such as grenades, land mines, missiles, bombs, etc.), and other weapons which rely on heat or burning are not cold weapons.

A dagger is a knife with a very sharp point and usually two sharp edges, typically designed or capable of being used as a thrusting or stabbing weapon. Daggers have been used throughout human history for close combat confrontations, and many cultures have used adorned daggers in ritual and ceremonial contexts. The distinctive shape and historic usage of the dagger have made it iconic and symbolic. A dagger in the modern sense is a weapon designed for close-proximity combat or self-defense; due to its use in historic weapon assemblages, it has associations with assassination and murders. Double-edged knives, however, play different sorts of roles in different social contexts. In some cultures, they are neither a weapon nor a tool, but a potent symbol of manhood; in others they are ritual objects used in body modifications such as circumcision.