The highest production value is 500000$ for 200000 units- the lowest production value is 200000$ for 100000 units- sales= 300000$ for 50000 units

contribution margin = Sales Price per unit - Total Variable cost per Unit

                    Answer B -3

B ------------------------------------------------------------------------------------

3

Variable cost per unit = ()/()=  3 per unit

Sales price per unit =300000/50000 =6 per unit

Contribution per unit =3 per unit

(B) is the Correct Ans.

Using High Low Method,

$500,000 - $200,000 /200,0000 -100,000 =  $3 Variable Cost Per Unit 

So,

Sale Price Per Unit = $300,000 /50,000 =  $6 Per Unit

And Contribution Per unit is =6 -3 =3

variable cost /unite=/=$3/unit

selling price=300000/50000=$6/unit

Contribution margin per unit=6-3=$3

So answer B

calculation of contribution margin per unit :

   Selling price per unit                                 = Sales price / sales unit

                                                                         = $300,000/50,000

                                                                         =$6 per unit

less: Variable cost per unit:

        =(Highest-lowest Total production cost)/(Highest volume-lowest volume)

        =$(500,000-200,000)/(200,000-100,000)

                                                                          =$3

  Contribution margin per unit                      $3

Hence B-3 is the correct answer