How Does IFRS Differ from GAAP When Accounting for Defined-Benefit

How does IFRS differ from GAAP when accounting for defined-benefit pension plans?

A) IFRS requires current period expensing of prior service costs while GAAP amortizes prior service costs over time.
B) GAAP allows companies to add interest cost and deduct expected return from pension expense in non-operating income. IFRS allows the net interest (from PBO and plan assets) to be reported in operating or financing income.
C) GAAP requires separate rates of interest for the PBO and expected return on plan assets. IFRS uses the same rate for both.
D) GAAP amortizes current year net actuarial gains and losses using the corridor approach, while IFRS does not amortize actuarial gains/losses. IFRS reports actuarial gains/losses in other comprehensive income.