During the end-of-period physical inventory count some of the inventory was not counted. This caused ending inventory to be understated (too low) by $18,000. If the company uses the periodic inventory system and the FIFO inventory costing method, then the effect of this error in the current period is: a) The error in cost of sales and net earnings is not determinable given the information provided. b) Cost of sales would be understated and net earnings would be overstated. c) Cost of sales would be overstated and net earnings would be understated. d) Both cost of sales and net earnings would be understated. e) Both cost of sales and net earnings would be overstated.