The following incomplete (columns have missing amounts) pension spreadsheet is for Old Tucson Corporation (OTC).

($ in millions) debit (credit)	PBO			Plan assets				Prior service cost				Net (Gain) loss				Pension Expenses				Cash				Net Pension (Liability)/ Asset
Beginning Balance	(480	)											54
Service cost																	56
Interest cost
Expected return on assets																	(21	)
Gain/loss on assets													(2	)
Amortization of:
Prior service cost									(5	)
Net gain loss
Loss on PBO	(23	)											23
Contribution to funds																					(50	)
Retiree benefits paid	39				(39	)
Ending balance	(552	)			277				50				72												(275	)

What was the prior service cost at the beginning of the year?

Multiple Choice

• $55 millions

• $52 millions

• $50 millions

• $45 millions