"(1) Since the Industrial Revolution, people have been working to protect the environment from the negative effects of manufacturing. (2) Industrial processes use massive amounts of energy and create harmful waste in the process, making them an ecological nightmare. (3) Some proposed solutions to this excessive waste do exist, but manufacturing systems need to be entirely rethought to best align with both human and environmental interests. (4) Closed-loop manufacturing is the only solution." In sentence 3 (reproduced below), the writer wants to acknowledge an alternative perspective about the issue of environmentally harmful manufacturing waste.
Some proposed solutions to this excessive waste do exist, but manufacturing systems need to be entirely rethought to best align with both human and environmental interests.
Which version of the underlined text best accomplishes this goal?

A. Many activists believe that the onus falls on individual consumers
B. No one knows for sure the best way to address the effects of the Industrial Revolution
C. There are few activists who doubt that manufacturing matters
D. More research must be done to determine the severity of the effects of manufacturing