Final answer:
The auditor must disclose the situation in the auditor's report.
Step-by-step explanation:
The correct answer is c. Disclose the situation in the auditor's report.
When an auditor's client violates a minor requirement of its bond indenture, it is important for the auditor to disclose this information in the auditor's report. This disclosure ensures transparency and provides relevant information to users of the financial statements.
Contacting the bond trustee directly or obtaining an opinion from the company's attorney may be appropriate steps in certain circumstances, but in this scenario, the auditor's main responsibility is to disclose the situation in the auditor's report.