Utilize the input text as a context reference, choose the right relationship between Air China and Shenzhen Airlines 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.

Shenzhen Airlines has struck a $4.3 billion deal to buy 46 Boeing 737s, parent Air China said last month, as the group looks to fly more routes.

Answer: business_division