Take context from the input text and decide on the accurate relationship between 'Lehman Brothers' and 'investment bank' from the options provided.
Options: member of, employer, brand, product/material produced

In 2009, a year after the collapse of investment bank Lehman Brothers and with the economy already in the depths of an historic, deep recession, economists were predicting the Fed would hike rates as early as the first quarter of 2010.
product/material produced