Welch Company accounts for a product it sells using the LIFO periodic inventory procedure. Merchandise inventory on January 1 was 3,000 units at $14.40 each. Product data for the year ended December 31, 2019, are as follows: Sales Purchases Unit Unit Cost Unit Unit Cost @ @ a January 5 March 31 August 12 December 26 6,000 18,000 12,000 6,000 $9.00 10.80 13.50 14.40 January 10 April 2 August 22 December 24 4,000 15,000 16,000 3,000 $14.40 16.20 18.00 19.80 @ @ @ a. Compute the gross margin earned on sales of this product for 2019. b. Repeat part a, assuming that the December 26 purchase was made in January of 2020. C. Recompute the gross margin, assuming that 10,000 rather than 6,000 units were purchased on December 26 at the same cost per unit. d. Solve parts a, b, and c using the FIFO method