The following information pertains to Houston Corporation's defined benefit pension plan:

($ in thousands)	2021 Beginning balances				2022 Beginning balances
Projected benefit obligation	$	(6,600	)		$	(7,104	)
Plan assets		6,360				6,936
Prior service costAOCI		660				600
Net lossAOCI	$	780			$	846

At the end of 2021, Houtston contributed $665 thousand to the pension fund and benefit payments of $654 thousand were made to retirees. The expected rate of return on plan assets was 10%, and the actuary's discount rate is 8%. There were no changes in actuarial estimates and assumptions regarding the PBO. What is the 2021 service cost for Houston's plan?

Multiple Choice

• $510 thousand.

• $630 thousand.

• $367 thousand.

• Cannot be determined from the given information.