Answer: d) Productivity
Step-by-step explanation:
One of the reasons an employee may be promoted is their productivity. To the employer, increasing the salary of a productive employee makes sense because the salary increase would simply come from the increased revenue brought in by the productive employee.
The employee in this scenario shows a strong work ethic by arriving early and has the best rapport with customers which means that they are hardworking as this is what gets customers to notice employees. This productivity is the reason this employee's wages were increased.