Answer:
a.$3.35
Explanation:
The first step in determining  conversion cost per unit is to calculate the Total Equivalent units of production for Conversion Costs.
Conversion Costs
Units Completed and transferred (15,000 × 100%) = 15,000
Units in Ending Work In Process (3,000 × 75%)      =  2,250
Total Equivalent units of production                        =  17,250
The next step is to determine the total conversion cost of production incurred during the period.
Conversion Costs
Conversion Costs in Beginning Work In Process                               $4,800
Conversion Costs added during the period ($33,000 + $20,000) $53,000
Total Conversion Costs                                                                      $57,800
Finally calculate the conversion cost per unit
Conversion cost per unit = Total Conversion Costs  / Total Equivalent units of production
                                          = $57,800 / 17,250
                                          = $3.35 (to the nearest cent)