Metallurgy was well known by the Guptas,.as can be attested to by the iron pillar of Delhi. The correct option among all the options that are given in the question is the third option. This pillar is a glowing example of the metallurgical advancement that the Guptas had during that time. This pillar has not rusted for a long time.
No there were also other people that join them
The Senate refused to ratify the treaty of Versailles primarily because they objected to the League of Nations. If the US joined the League, then they would be obligated to fight in future wars and the Senate didn't want that.
