OGDCL, a public listed company has 24 million stocks outstanding. Next year's dividend is expected to be Rs. 2.80 per share. Dividends have been growing at 5% per year over the last several years and are expected to continue at the same growth rate over the foreseeable future. The stock is currently traded at Rs. 20 per share. OGDCL bonds which have 8% yield to maturity and a 7.2% coupon rate are selling at their par value of Rs.1,000 each. Finally, OGDCL preferred stocks of which there are one million, have a fixed dividend of Rs 2.00 each and are currently selling at Rs14.30 per share. The company's tax rate is 28%. i. Calculate OGDCL appropriate weighted average cost of capital (WACC). ii. What is meant by optimal capital structure? Why does it vary by industry?