<Tr> <Td> Denmark </Td> <Td> Danish colonial empire </Td> <Td> Emil Vind </Td> </Tr> <Tr> <Td> Spain </Td> <Td> Spanish colonial empire </Td> <Td> Francisco Merry y Colom </Td> </Tr> <Tr> <Td> United States </Td> <Td> Territories of the United States </Td> <Td> John A. Kasson Henry S. Sanford </Td> </Tr> <Tr> <Td> France </Td> <Td> French colonial empire </Td> <Td> Alphonse de Courcel </Td> </Tr>

European interest in the congo is due primarily to which of the following