<Tr> <Td> Austria - Hungary </Td> <Td> 3,000 </Td> <Td> 100,000 </Td> </Tr> <Tr> <Td> United States </Td> <Td> 1,462 </Td> <Td> 72,807 </Td> </Tr> <Tr> <Td> Italy </Td> <Td> 4,627 </Td> <Td> 60,000 </Td> </Tr> <Tr> <Td> Total </Td> <Td> 90,198 </Td> <Td> 1,230,853 </Td> </Tr>

Which of the following is the reactive chemical warfare agent first used in world war 1