Answer:
a. It uses multiple work-in-process accounts for manufacturing firms.
Explanation:
"Companies use process cost systems to apply cost to similar products that are mass-produced in a continuous fashion.
[...] companies track costs through a series of connected manufacturing processes or departments, rather than by individual jobs. Thus, companies use process cost systems when they produce a large volume of relatively homogeneous products"
Reference: Weygandt, J. J., Kimmel, P. D., & Kieso, D. E. (2009). Managerial accounting: tools for business decision making. John Wiley & Sons. pp 100-101