b$.$ If the expected annual sales for the product is $700$ units, which process would you choose?

A$.$ Since the production volume at which the second manufacturing process becomes more attractive is higher than the expected annual sales for the product, you should choose the first manufacturing process.

B$.$ Since the production volume at which the second manufacturing process becomes more attractive is lower than the expected annual sales for the product, you should choose the first manufacturing process.

C$.$ Since the production volume at which the second manufacturing process becomes more attractive is higher than the expected annual sales for the product, you should choose the second manufacturing process.

D$.$ Since the production volume at which the second manufacturing process becomes more attractive is lower than the expected annual sales for the product, you should choose the second manufacturing process.