Labor representative: Social historians have shown conclusively that if workers strike when the working conditions at their jobs are poor, those conditions usually significantly improve after five years. Although workers in this industry are familiar with this fact, they nonetheless refuse to strike even though their working conditions are poor. Which one of the following, if true, most helps to resolve the apparent discrepancy described by the labor representative? ['Wages in this industry have increased each year.', 'Workers typically plan to work in this industry only three years.', 'Working conditions in many other industries are worse than conditions in this industry.', 'Most factories in this industry change ownership every two years.']