answer this question for rio tinto as the company include academic sources and articles with url and references: b$)$ An evaluation of the company's capital structure policy and establish a link with its cost of capital.

Discussion of the capital structure policy of the chosen firm used in practice. Discussion should focus on the overall impact on shareholders$$ wealth by providing a linkage among the choice of capital structure, the cost of capital and the valuation of the firm. You can use the relevant variables from financial statements or databases to establish the linkage.