A product requires four parts that are made on the same lathe. Call the parts A, B, C, and D. The product requires 1 unit of A, 2 of B, 4 of C, and 8 of D. Which of the following production cycles is most appropriate? 

a. A: 100, B: 100, C: 100, D: 100 

b. A: 101, B: 102, C: 104, D: 108 

c. A: 100, B: 150, C: 200, D: 400 

d. A: 100, B: 200, C: 400, D: 800