Under U.S. GAAP, interest cost included in the net pension cost recognized for a period by an employer sponsoring a defined benefit pension plan represents the: a. Shortage between the expected and actual returns on plan assets. b. Increase in the projected benefit obligation due to the passage of time. c. Increase in the fair value of plan assets due to the passage of time. d. Amortization of the discount on unrecognized prior service costs. Under U.S. GAAP, interest cost included in the net pension cost recognized for a period by an employer sponsoring a defined benefit pension plan represents the: a. Shortage between the expected and actual returns on plan assets. b. Increase in the projected benefit obligation due to the passage of time. c. Increase in the fair value of plan assets due to the passage of time. d. Amortization of the discount on unrecognized prior service costs