Utilize the input text as a context reference, choose the right relationship between Ma Zhaoxu and ambassador from the options. Options: product/material produced, manufacturer, distributed by, industry, position held, original broadcaster, owned by, founded by, distribution format, headquarters location, stock exchange, currency, parent organization, chief executive officer, director/manager, owner of, operator, member of, employer, chairperson, platform, subsidiary, legal form, publisher, developer, brand, business division, location of formation, creator.

China's ambassador Ma Zhaoxu is set to express concerns the agreement could slip through the pair's fingers, as the opposition argues for safeguards to protect local jobs.

Answer: position_held