Setting TMP_Dropdown value through a script

I am trying to populate my TM drop down menus with the data in my ScriptableObject. As simple as this question may be, I still haven't found an answer.
This is what I think is the best I have. I tried using numeric values, etc.

Code (CSharp):

1. // tmText is TM_Text, the dropdown label
2. // tmDrop is TM_Dropdown, the actual drop down
3.  
4.         PreferenceSettings settings = GameController.Controller.GetSettings();
5.  
6.         if (settings.textureQuality == Quality.LOW)
7.         {
8.             tmText.SetText("LOW");
9.             tmDrop.captionText = tmText;
10.         }
11.         else if (settings.textureQuality == Quality.MEDIUM)
12.         {
13.             tmText.SetText("MEDIUM");
14.             tmDrop.captionText = tmText;
15.         }
16.         else if (settings.textureQuality == Quality.HIGH)
17.         {
18.             tmText.SetText("HIGH");
19.             tmDrop.captionText = tmText;
20.         }
21.  

Please help