Montague amended its pension plan 5 years ago, and created 75000 of prior services cost.Each year since then, pension expense included amortization of prior services cost 5000. At the end of current year the balance of prior services cost in AOCI will be

a. 25000 in credit

b.50 000 in credit

c.25 000 in debit

d.50 000 in debit