Answer and Explanation:
The Journal entry is shown below:-
1. Pension Account Dr, $18
Plant assets (expected return on assets) Dr, $14
    To PBO $28
($20 + $8)
    To Net loss - AOCI (current amortization) $4
(Being pension and plant assets is recorded)
2. Pension Account Dr, $20
Plant assets (expected return on assets) Dr, $12
Net gain—AOCI (current amortization) Dr, $4
    To PBO $36
($20 + $16)
(Being pension, plant assets and net gain is recorded)
3. Â Pension Account Dr, $33
Plant assets A/c (expected return on assets) Dr, $12
    To Net loss—AOCI (current amortization) $4
    To PBO $36
($20 + $16)
     To Prior service cost A/c (current amortization) $5
(Being pension and plant assets and pension account is recorded)