Brian and his roommate Anthony are studying the differences between variable and absorption costing for their upcoming quiz. Anthony is quite sure that he can predict the difference in income from one costing system to the next just by knowing the following four items for a given period. (a1) Given just these items, can Anthony calculate the difference in operating income between variable and absorption costing for this period? If so, calculate the difference. (If the difference cannot be calculated enter 0 for the amount. Do not leave answer field blank.) Income difference Specify which costing system will show the higher income