What is the relationship between 'Apple Inc' and 'iPhone' in the context of the input sentence.
Options: location of formation, founded by, headquarters location, product/material produced

The housing index (.HGX) rose 1.64 percent on the data, outperforming the overall stock market, which fell after Apple Inc (AAPL.O) late on Tuesday gave a fourth-quarter revenue forecast that fell short of estimates and missed some targets for iPhone sales.
product/material produced