The correct options are
A Evidence of iron smelting has been found in Kodumanal and Guttur.
C The Sangam Age has its roots in the Iron Age.
Evidences of iron Smelting along with terracotta pipes and raw ore have been discovered at various archaeological sites such as Kodumanal and Guttur.
Punch marked coins were the earliest coins in India. They are mostly made of Silver.
Archaeologically, the Tamil Sangam Era corresponds roughly to the late Iron Age-Early Historic period (300 BCE to 300 AD). It represents a key stage in the development of South Indian material culture.
The historic text titled 'Natural History' written by 'Pliny the Elder' talks about the ancient Tamil civilisation. It also talks about the pepper trade that the Romans had with India.