Take context from the input text and decide on the accurate relationship between 'Mary Barra' and 'chief executive officer' from the options provided.
Options: position held, industry, director/manager, product/material produced

GM chief executive officer Mary Barra told reporters in June that she would not negotiate with the UAW in public and preferred to keep any discussions behind closed doors -- a policy both sides have adhered to since talks began last month.
position held