The correct answer is option 2: Sonorous. School bells are made of metals because metals have the property of being sonorous.

Sonorous means the ability to produce a loud, clear, and ringing sound when struck. Metals have this property because they have loosely bound electrons that are free to move within the metal lattice. When a metal object, such as a school bell, is struck, the force causes the metal atoms to vibrate, which in turn creates sound waves that travel through the air, resulting in a ringing sound.

Let`s analyze the other options to see why they are not the correct answers in this context:

Option 1: Malleable. Malleability refers to the ability of a material to be hammered or rolled into thin sheets. While some metals are indeed malleable, this property is not directly related to the sound-producing characteristics of a school bell.

Option 3: Ductile. Ductility refers to the ability of a material to be drawn into a thin wire. While some metals are ductile, this property is also not directly related to the sound-producing characteristics of a school bell.

Option 4: Lustrous. Luster refers to the shininess or reflectivity of a material. While metals are generally l