A quality control manager wants to determine the percentage of defective light bulbs in the production line. Which of the following sampling methods would most likely lead to a valid inference? (1 point)

O testing the first 2,000 light bulbs in the production line
O retesting 100 light bulbs that have already been tested
O testing every fiftieth light bulb in the production line
• testing the last 4,000 bulbs in the production line

Testing every fiftieth light bulb in the production line would most likely lead to a valid inference, as it provides a systematic and random sampling method that allows for a representative sample of the entire production line.