Your network contains a server that has Microsoft SharePoint Foundation 2010 installed.
The farm account for the server is named Service1.
You need to automatically change that the password for Service1 every 30 days.

What should you do?

A.
From ADSI Edit, create a Password Settings object (PSO).

B.
From Windows PowerShell, run the NewADServiceAccount cmdlet.

C.
From Windows PowerShell, run the InstallADSserviceAccount cmdlet.

D.
From Central Administration, modify the properties of the Service1 managed account.

Explanation:
Register Managed Accounts (SharePoint Central Administration)
To register new Managed Accounts using SharePoint Central Administration, select Security from the SharePoint Central Administration homepage.
On the Security page select Configure managed accounts under General Security.
On the Managed Accounts page select Register Managed Account.
On the Register Managed Account page specify the credentials and select the password change policies as desired.

Source: http://blogs.technet.com/b/wbaer/archive/2010/04/11/managed-accounts.aspx