At a certain company, an employee who meets each of the criteria below qualifies for full retirement benefits
• The number of years, x, the employee has been employed by the company is at least 25 years.
• The employee's age, y, is at least 55 years.
• The sum of the employee's age and number of years employed by the company is at least 90 years.
Which of the following systems represents the criteria an employee of the company must meet in order to
qualify for full retirement benefits?