The correct answer is C. policy.
A policy is a general principle or guideline that is used to make decisions. It is a higher-level concept than rules, procedures, or methods. Rules are specific instructions that must be followed. Procedures are step-by-step instructions for completing a task. Methods are ways of doing something.
In the example, “Employees will be promoted on the basis of seniority,” the policy is that employees will be promoted based on how long they have been with the company. This is a higher-level concept than rules, procedures, or methods. Rules would be more specific instructions about how to determine seniority, such as how to calculate years of service. Procedures would be step-by-step instructions for how to promote employees, such as how to fill out a promotion form. Methods would be ways of determining seniority, such as looking at employee records or interviewing employees.
In conclusion, the correct answer is C. policy.