Can you explain this to me$?$ I have no idea how to do this? Thanks

Mill Corporation had the following unit costs for the recently concluded calendar year: Variable Fixed $8.00 $3.00 Manufacturing $2.00 $5.50 Non-manufacturing Inventory for Mill's sole product totaled 6,000 units on January T and 5,200 units on December 31. When compared to variable costing income, Mills absorption costing income is Select one: $2,400 $2,400 higher. $6,800 lower. $6,800 higher. Check