Utilize the input text as a context reference, choose the right relationship between 'Ma Zhaoxu' and 'ambassador' from the options.
Options: owner of, business division, chief executive officer, position held

On Tuesday night, China's ambassador to Australia Ma Zhaoxu told a business function in Melbourne that the FTA was a "hard-won and historic opportunity" which should "not be allowed to slip through our fingers".
position held