Final answer:
Service cost is the expense caused by the increase in the accumulated benefit obligation because of employees' service during the current year.
Step-by-step explanation:
The statement that service cost is the expense caused by the increase in the accumulated benefit obligation because of employees' service during the current year is true. Service cost is a component of pension expense that represents the cost of the future benefits earned by employees as a result of their service in the current year. It is calculated based on actuarial assumptions and reflects the increase in the present value of the pension benefits due to the additional year of service.