(a) With regard to defined benefit pension plans, explain each of the following terms:

(i) Defined benefit obligation.

(ii) Current service cost.

(iii) Interest cost. 

(iv) Actuarial gains and losses.

(b) Identify the main components of the defined benefit expense which should be shown in an employer's statement of comprehensive income.

(c) Identify the main components of the defined benefit liability which should appear in the employer's statement of financial position.