Answer:
c) $9,000,000
Explanation:
The cost of good sold = Cost per unit × Quantity sold
   Quantity sold = 300,000, cost per unit = $30
The cost of sold = $30 × 300,000 =  $9,000,000 
This can be confirmed as follows:
                                                                   Unit
opening inventory                                     80,000
Production(see note below)                    <u> 340,000</u>
Available or sale                                       420,000
Closing inventory                                    <u>(120,000)</u>
Units sold                                                 <u>300,000</u>         
Cost of units sold = 300,000 × $30 = $9,000,000
Note :
Production budget = sales budget + closing inventory - opening inventory 
 = 300,000 + 120,000 - 80,000 = 340,000 units