Cell Company has discovered that the cost of processing customer invoices is strictly variable within the relevant range. Which one of the following statements concerning the cost of processing customer invoices is incorrect?

Multiple Choice

The average cost per unit for processing a customer invoice will equal the incremental cost of processing one more customer invoice.

The cost of processing the $100$th customer invoice will be the same as the cost of processing the first customer invoice.

The total cost of processing customer invoices will increase as the volume of customer invoices increases.

The cost per unit for processing customer invoices will decline as the volume of customer invoices increases.