Answer:
 they need to limit the material and labor costs to $22.75
so correct option is c. $22.75
Step-by-step explanation:
given data 
promotion and sales = $3 million
contribution margin = 35%
Selling price = $35.00
to find out 
what would they need to limit the material and labor costs to
solution
we get first here Contribution margin per unit that is 
Contribution margin = contribution margin × Selling price ..............1
Contribution margin = $35 × 35%
Contribution margin = $12.25 per unit 
 and 
Variable cost will be 
Variable cost = Selling price - Contribution margin ..............2
Variable cost = $35 - $12.25 
Variable cost = $22.75 per unit 
and 
Variable cost = Direct materials costs + Direct labor costs + Direct factory overheads ...............3
here direct factory overheads is given = 0 
 so 
$22.75 = Direct materials costs + Direct labor costs 
so 
 they need to limit the material and labor costs to $22.75
so correct option is c. $22.75