The correct options are
A 24 feet high iron pillar, Vijay Stambha, which has not yet corroded.
B 18 feet high copper statue of Buddha discovered in Nalanda.
D Nalanda University was equipped with furnace for study and research.
Ancient India saw various developments in the field of chemistry. Some examples of phsyical evidence include the copper statue of Buddha discovered in Bihar which is 7 ½ feet high and weighs a tonne while the statue of Buddha at Nalanda that is 18 feet high. Another example is the Vijay Stambha at Delhi, a 24 feet high iron pillar built by Chandragupta II, that weighs a massive 7 tonnes and has not yet corroded.