Yes Co. has the option to either further process product Y to produce Product Z. The selling price of product Y is $30 per unit and it costs $28 to produce each unit of produ Y. Product Z would be...

Yes Co. has the option to either further process product Y to produce Product Z. The selling price of product Y is $30 per unit and it costs $28 to produce each unit of produ Y. Product Z would be sold for $55 and would require an additional $31 cost for production. What is the differential cost to produce product Z?
a. $3 per unit
b. $28 per unit
c. $31 per unit
d. $25 per unit