Evaluate the capital structure of Amazon.com Inc. and recommend an optimal debt-to-equity ratio based on the following financial metrics for the fiscal year 2023:

• Debt Ratio: 0.4
• Equity Ratio: 0.6
• Weighted Average Cost of Capital (WACC): 8%
• Cost of Debt: 5%

Capital structure optimization involves determining the ideal mix of debt and equity financing to maximize shareholder value and minimize the cost of capital. Analyze Amazon.com Inc.'s capital structure using the provided financial metrics and recommend an optimal debt-to-equity ratio to enhance the company's financial performance and cost of capital efficiency. This analysis aids in strategic decision-making and capital allocation to support long-term growth and profitability.