Anybody knows why I am not getting Firefox option in the dropdown "Open the following browser when a record or run session begins" when we go to record and run settings. I am using UFT 11.50. It shows 2 options IE and Chrome but no Firefox.

I am using VBscript to design my testing script primarily with IE but I need to run them in Firefox too.
I have Firefox 19.0.2 installed on my machine