Answer:
C) $4.02
Explanation:
The computation of cost per equivalent unit for processing cost for March is shown below:-
As we know that 
Beginning work in process inventory units + Units started into production  = Ending work in process inventory units + Units completed and transferred out
60,000 + 190,000 = Units in ending work in process inventory + 200,000
Units in ending work in process inventory is
 = 60,000 + 190,000 - 200,000
= 50,000
To complete the beginning work in process inventory:-      
Processing:                                                     24,000
60,000 units ×(100% - 60%) a
Units started and completed                          140,000
(200,000 − 60,000) b
Ending work in process inventory Processing:
50,000 units × 20% c                                      10,000
Equivalent units of production                        174,000
Cost added throughout the period e            7,00,000
Equivalent units of production f                     174,000
Cost per equivalent unit e ÷ f                             $4.02