The most improved brand is General Motors (NYSE: GM ) ("CEO Mary Barra has made it her goal to ... make sure errors of the past are not forgotten and not repeated"), followed by Target (NYSE: TGT ), travel website Trivago and GM brands Chevrolet and Buick.
Take context from the input text and decide on the accurate relationship between 'Mary Barra' and 'General Motors' from the options provided.
Options: operator, director/manager, employer, brand