$\backslash$table$[[,1,2,3,4,5,6],[$Inputs$],[\backslash$table$[[$Forecasted$],[$demand$]],100,125,120,80,75,70],[\backslash$table$[[$Workforce$],[$Level$]],80,80,80,80,80,80],[$Part Time,$12,12,12,12,12,12],[\backslash$table$[[$Beginning$],[$inventory$]],20,$C$,0,0,0,0],[\backslash$table$[[$Ending$],[$inventory$]],12,0,0,0,0,$B$],[$Backlog$,0,21,$A$,37,20,0]]$

Use the information in the table above. What will be the backlog at the end of period $3($A$)?$

$49$

$0$

$37$

$21$