On January 1, 2008, Prada Corp. adopted a defined-benefit pension plan. The plan's service cost of $300,000 was fully funded at the end of 2008. Prior service cost was funded by a contribution of $120,000 in 2008. Amortization of prior service cost was $48,000 for 2008. What is the amount of Prada's prepaid pension cost at December 31, 2008?
a. $180,000
b. $168,000
c.$72,000
d. $120,000