Brown Corp's defined benefit pension plan covers $200$ employees. Brown amends its pension plan on Jan $1,2021$ and grants $$86,000$ of prior service costs to its employees. The employees are grouped based on their expected service years before retirement:

$\backslash$table$[[$Group$,$Number of employees,$\backslash$table$[[$Expected retirement on Dec$],[31.]]],[$A$,50,2021],[$B$,70,2022],[$C$,80,2023],[$Total$,200,]]$

Calculate Brown's $2022$ annual amortization of prior service cost using years$-$of$-$service method.

$$86,000$

$$40,000$

$$30,000$

$$16,000$