asterisk users - Nov 2005 - How to disable SIP Options methods on asterisk

Hi there:

I have a running asterisk ver 1.2 box. It supports the following SIP methods:

INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY

If I want to disable OPTIONS method, what can I do on the sip setting
files? Or I need to have an alternative way to reach it?

Thank you for your help.

Wilson