Jquery Disable option in dropdown

Question

Guys i have used the following code to disable an option using jQuery (jquery-1.4.2.min).The disable happens in Firefox , but not in IE.

<SELECT NAME="SCOPE" id="SCOPE">  
 <OPTION VALUE="G"> Global
 <OPTION VALUE="D"> Dynamic  
</SELECT>


 $("#SCOPE option[value='G']").attr("disabled","disabled");
 $("#SCOPE option[value='D']").attr("selected", "selected");