What is the relationship between Air China and Shenzhen Airlines in the context of the input sentence. Choose an answer from: 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