Analyze the relationship between 'Apple Inc' and 'iPhone' within the context of the input sentence.
Options: product/material produced, publisher, chief executive officer, brand

SAN FRANCISCO, Sept 9 (Reuters) - Apple Inc unveiled the iPhone 6S and 6S plus on Wednesday, the latest iteration of its lucrative smartphone that offers 3D touch, a display technology that responds differently depending on how hard users press their screens.
product/material produced