Who among the following is credited with giving the first-ever atomic theory of matter?

Kanada (also known as Kashyapa) founded the Vaisheshika school of Hindu philosophy, which proposed that all matter is composed of indivisible atoms called 'paramanu'. This atomic theory dates back to around 6th-2nd century BCE, making it one of the earliest atomic theories in the world. The other options were mathematicians and astronomers but not associated with atomic theory.