In the context of the input sentence, determine the relationship between 'Johannes Stroebel' and 'New York University'.
Options: founded by, brand, chief executive officer, employer

An NBER working paper* published this week by Sumit Agarwal of the National University of Singapore, Souphala Chomsisengphet of the Treasury Department, Neale Mahoney of the University of Chicago and Johannes Stroebel of New York University looks at data from hundreds of millions of credit cards from 2008 to 2014 to work out why the results were so disappointing.
employer