What is the relationship between Apple Inc and iPhone 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.

BENGALURU/SAN FRANCISCO (Reuters) - Apple Inc (AAPL.O) shares slumped nearly 7 percent in after-hours trading as its fourth-quarter revenue forecast fell short of estimates and it missed some targets for iPhone sales.

Answer: product_or_material_produced