Which of the following statements is incorrect concerning warranties?

Question $14$Select one:

a$.$

Using the expense approach, the warranty is provided with the product or service with no additional fee.

b$.$

Where warranty costs are immaterial or when the warranty period is quite short, the warranty costs may be accounted for using the cash basis.

c$.$

Using the revenue approach, the warranty is a separate deliverable from the related product or service.

d$.$

The revenue approach must be used for income tax purposes