Can some one me learn linear equations

If jobs have been undercosted due to underallocation of manufacturing overhead, then cost of goods sold (cogs) is too low and which of the following corrections must be made? a. decrease cogs for double the amount of the underallocation b. increase cogs for double the amount of the underallocation c. decrease cogs for the amount of the underallocation d. increase cogs for the amount of the underallocation