What is the relationship between 'Brian Hartzer' and 'Westpac' in the context of the input sentence.
Options: distributed by, headquarters location, employer, publisher

Brian Hartzer, Westpac chief executive Westpac chief executive Brian Hartzer said in a memo sent to the bank's staff on Friday that Disney is "one of the world's most loved brands and their Next Generation Experience program has set a new benchmark for how great service can be delivered in a digitally-enabled world".
employer