Utilize the input text as a context reference, choose the right relationship between 'iPhone' and 'Apple Inc' from the options.
Options: manufacturer, owner of, subsidiary, position held

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.
manufacturer