Read this and answer the question. If the question is unanswerable, say "unanswerable".

The company's 14 member Board of Directors is responsible for overall corporate management. As of Cathie Black's resignation in November 2010 its membership (by affiliation and year of joining) included: Alain J. P. Belda '08 (Alcoa), William R. Brody '07 (Salk Institute / Johns Hopkins University), Kenneth Chenault '98 (American Express), Michael L. Eskew '05 (UPS), Shirley Ann Jackson '05 (Rensselaer Polytechnic Institute), Andrew N. Liveris '10 (Dow Chemical), W. James McNerney, Jr. '09 (Boeing), James W. Owens '06 (Caterpillar), Samuel J. Palmisano '00 (IBM), Joan Spero '04 (Doris Duke Charitable Foundation), Sidney Taurel '01 (Eli Lilly), and Lorenzo Zambrano '03 (Cemex).

What chemical company is Cathie Black affiliated with?
unanswerable