He is supported by a very strong leadership team and I am confident he will build on the excellent progress Bill has made in optimising the performance of the asset-base, specifically increasing marketable shipments and reducing costs through debottlenecking and efficiency improvements," Lakshmi Mittal said, also indicating: "I would also like to take this opportunity to thank Bill, who has been a tremendous asset to ArcelorMittal over the past thirteen years and has made a considerable contribution to our company.
What is the relationship between 'ArcelorMittal' and 'Lakshmi Mittal' in the context of the input sentence.
Options: employer, position held, chief executive officer, parent organization