Option (a) is incorrect: This statement is a supporting argument in the passage, but it is not the central theme. The passage focuses on how good corporate governance improves the credibility of firms, rather than just ensuring access to external financing.

Option (b) is correct: This statement best reflects the logical inference from the passage as it highlights how good corporate governance structures encourage companies to provide accountability and control, leading to greater investment, higher growth, and employment. The passage emphasizes that effective corporate governance enhances access to external financing by firms, which in turn attracts investors who look for standards of disclosure, timely and accurate financial reporting, and equal treatment to all stakeholders. Therefore, the central theme of the passage is how good corporate governance plays a crucial role in improving the credibility of firms in the eyes of investors and international capital markets.

Option (c) is incorrect: This statement is not directly supported by the passage. The passage mentions that the rapid growth in international capital markets has led to corporate governance being on the economic and political agenda worldwide, but it does not state that international capital markets ensure firms maintain good corporate governance.

Option (d) is incorrect: This statement is not supported by the passage. The passage does not mention supply chains in relation to corporate governance.