among various concepts of capacity for calculating the cost of each unit produced. unfavorable $($U$).)$

$\backslash$table$[[,$Theoretical,Practical$],[$Revenue$,$$$,2,880,000,],[$Less: Cost of Goods Sold,,$(1,050,000),],[$Production$-$Volume Variance,,$(780,000),$U$,],[$Gross Margin,,$1,050,000,,],[$Variable Selling,,$(75,000),,],[$Fixed Selling,,$(240,000),,],[$Operating Income,$$,735,{000}_{?},,]]$

Data table

$\backslash$table$[[$Theoretical capacity,$900,000$ bulbs$],[$Practical capacity,$520,000$ bulbs$],[$Normal capacity,$260,000$ bulbs $($average expected output for the next three years$)],[$Master$-$budget capacity,$225,000$ bulbs expected production this year$]]$

Requirements

If $GBL$ sells all $300,000$ bulbs produced, what would be the effect on operating income of using each type of capacity as a basis for calculating manufacturing cost per unit?

Compare the results of operating income at different capacity levels when $225,000$ bulbs are sold and when $300,000$ bulbs are sold. What conclusion can you draw from the comparison?

Using the original data $($that is$,300,000$ units produced and $225,000$ units sold$)$ if GBL had used the proration approach to allocate the production$-$volume variance, what would operating income have been under each level of capacity? $($Assume that there is no ending work in process.$)$

Reference

$\backslash$table$[[,,\backslash$table$[[$Theoretical$],[$capacity$]],,\backslash$table$[[$Practical$],[$capacity$]],,\backslash$table$[[$Normal$],[$capacity$]],,\backslash$table$[[$aster$-$budget$],[$capacity$]]],[$Inventoriable cost per unit,$$,3\mathrm{.}50,$$$,4\mathrm{.}45,$$$,6\mathrm{.}70,$$$,7\mathrm{.}40],[$Production volume variance for$],[$actual production of $300,000$ bulbs,$$,780,000U,$$$,495,000U,$$$,180,000F,$$$,390,000F$