To achieve the highest wage possible, the most favorable characteristics would be found in the fourth option:
"There are many firms producing very popular products, but the production process is so technical that properly-trained employees are hard to come by."
This scenario suggests that there is a strong demand for skilled labor due to the technical nature of the production processes. Since properly-trained employees are scarce, those who possess the necessary skills can command higher wages. The combination of high demand, specialized skills, and a shortage of qualified workers typically leads to higher salaries in the industry.