Which of the following statements about the zone of insolvency is NOT true? O a. There is no test or definition for the zone of insolvency. O b. Creditors have a right to assert direct claims for breach of fiduciary duty against a firm's board of directors in the zone of insolvency. O c. Insolvency is usually defined as an inability to pay debts as they mature. Od. The scope of the duty owed to creditors by a firm in the zone of insolvency varies by jurisdiction