Answer:
Production unit will be 556 
So option (c) will be the correct option 
Step-by-step explanation:
We have given sales for cost for don = 505 units 
Digby wants to have an extra 10% units on hand beyond their forecast 
So reserve percentage = 10 % = 0.10
We have to find the total number of production unit 
We know that production unit is given by 
Production unit = Sales ( 1 + reserve percentage )
= 

So option (c) will be the correct option