Final answer:
Before the NUMMI partnership, the GM plant in Fremont was likely experiencing high internal failure costs due to poor work ethic, absenteeism, substance abuse on the job, and intentional sabotage, leading to defective products and manufacturing inefficiencies.
Step-by-step explanation:
The category of quality-related costs that were most obvious at the GM plant in Fremont before the NUMMI partnership was likely c) Internal Failures. Before the NUMMI partnership, the Fremont plant was notorious for its poor work ethic and quality problems.
The plant experienced high levels of absenteeism, alcohol and drug abuse on the job and deliberate acts of sabotage by disgruntled workers. These factors contributed significantly to defective products and inefficiencies in the manufacturing process, emblematic of internal failures. These costs are associated with defects that are found before the product reaches the customer, including scrap, rework, and process failures.