Analyze the relationship between 'Starbucks' and 'coffee' within the context of the input sentence.
Options: currency, distributed by, operator, product/material produced

Last year, they consumed 90 million gallons of ready-to-drink coffee beverages, ranging from bottled Starbucks Frappuchinos to cartons of Stumptown cold brew, up 52 percent from 2009, data from Beverage Marketing Corporation show.
product/material produced