CRM 2013 get option set value

Hi,

Here resoultion time is option set and am trying to get the option set value..but it's not working

can you pls suggest me on this

var resolution = RetrieveCategroyNames[0].attributes["resolutiontime"] != null ? RetrieveCategroyNames[0].attributes["resolutiontime"].getSelectedOption().Value : "";

Rammohan