Final answer:
Revolving lines of credit need to be excluded from the calculation of a firm's permanent debt, while long-term debt and mortgage debt are typically included due to their long-term nature.
Step-by-step explanation:
When calculating a firm's amount of permanent debt, certain types of debt must be considered. Permanent debt typically refers to long-term financing that a company uses to acquire assets or fund its operations.
The options provided are:
- Long-term debt
- Revolving lines of credit
- Mortgage debt
- None of the above
Long-term debt and mortgage debt are typically included in the calculation of permanent debt as they represent long-term obligations. However, revolving lines of credit are generally not considered permanent debt because they can be drawn down and paid off repeatedly. So, in this context, revolving lines of credit need to be excluded from the calculation of the firm's amount of permanent debt.