An advantage of a production line process is a. higher volume of output needed to justify the investment. b. greater degree of flexibility of the process. c. higher range of output typically produced on such a process. d. lower per unit cost of items produced on the line.

D. lower per unit cost of items produced on the line.

Explanation:

"The primary benefit of assembly lines is that they allow workers and machines to specialize at performing specific tasks, which can increase productivity. Large-scale assembly lines can allow for mass production of goods that would not be possible if products were made from start to finish by a single worker. The high productivity of mass production can also result in lower cost per unit produced than other manufacturing methods."

Reference: Hamel, Gregory. “Pros & Cons of Manufacturing Products With Assembly Lines.” Small Business - Chron.com, Chron.com, 21 Nov. 2017

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