What was the big gun that Sreedhar saw made up of?

Sreedhar, one of the characters of the story, saw a big gun, also known as cannon and called others to see it. It was used by the Mughal Emperor Aurangzeb while they were fighting with Golconda's Qutubshahi dynasty to gain control of the mighty fort. Wars at that time were fought using guns and weapons and animals like elephants and horses were employed. One such gun is canon. The cannon that they spotted was made using bronze, option B, which is a mixture of copper and tin.