<Tr> <Td> Atropatene </Td> <Td> 320s BC--3rd century AD </Td> </Tr> <Tr> <Td> Kingdom of Cappadocia </Td> <Td> 320s BC--17 AD </Td> </Tr> <Tr> <Td> Seleucid Empire </Td> <Td> 312--63 BC </Td> </Tr> <Tr> <Td> Kingdom of Pontus </Td> <Td> 281--62 BC </Td> </Tr>

Which best describes the type of government iran has