Answer:
The correct answer is - tin.
Step-by-step explanation:
Tin is the element that is mixed with copper to make bronze as bronze has many unique properties such as crisp sound quality and hardness. The hardness of the bronze allows them to make a good quality sound is come by adding tin to copper restricts the free flow of electrons of the copper atoms.
The pure metals have molecules present in an orderly manner and allow the electrons to free flow. This is why bell makers use bronze as it does not allow electrons to move freely which makes it hard and makes a good sound.