Which Statement Is Correct

Which statement is correct?

A) An unexpected gain on plan assets represents an unfavourable difference between actual and expected amounts of income from pension assets.
B) Actuarial gains and losses arising from the obligations of a pension plan derive from differences between the actual and expected values of the obligation.
C) IFRS requires actuarial gains and losses to be recorded the income statement.
D) An unexpected loss on plan assets represents a favourable difference between actual and expected amounts of income from pension assets.