How did new smelting techniques aid military expansion during the Bronze Age?

A. They contributed to the development of early gunpowder weapons.
B. They made armor ineffective and unnecessary for most soldiers.

CThey allowed for much stronger and more durable weapons.
DThey helped soldiers travel more quickly on horseback.

The Bronze Age is the period of prehistory in which the metallurgy of this metal was developed, the result of the copper-tin alloy. The technology related to the bronze was developed in the Near East at the end of the IV millennium a. C., dating in Asia Menorantes of 3000 a. C .; in ancient Greece it began to be used in the middle of the third millennium a. C .; in Central Asia the bronze was known around 2000 a. C., in Afghanistan, Turkmenistan and Iran, although in China it did not begin to be used until 1800 a. C., adopting the Shang dynasty.

The new ways of working with metal helped to develop and expand the use of weapons at the time, a clear example of which are the Otomani groups that developed in the Balkans, Hungary and Slovakia. Their towns present / display great fortifications and their ajuares have a greater proportion of arms that of useful, which confers them a clear warlike character. It seems that they had a great mobility, facilitated by the use of the horse and the car. The funerary rite was initially of individual burial under a tumulus.