Analyze the relationship between 'DFS' and 'furniture' within the context of the input sentence.
Options: owned by, position held, product/material produced, director/manager

2015 has been a positive year thus far for investors in potash exploration company Sirius Minerals (LSE: SXX), support services contractor Balfour Beatty (LSE: BBY) and furniture seller DFS (LSE: DFS).
product/material produced