Lillian Inc. has a defined benefit plan for its employees. The balance of the present value of the pension obligation as at December 31, 20X6, was $4,320,000. Relevant information with respect to the plan for 20x7 follows: Current service costs were $270,000 for 20X7 - accrued at year end. Contributions to the plan of $300,000 - paid on January 1, 20x7. Payments made to retirees of $190,000 - paid on July 1, 20x7. The appropriate interest rate to use is 5%. What is the closing balance of the pension plan on December 31, 20X7? a $4,188,750 b. $4,611,250 C. $4,624,750 d. $4,311,250