By default, if you enable the Show "Other" option, the answer will appear last in your list of answer options:
Assuming your answer options are using answer codes “SQ001”, “SQ002”, … you can use the following code snippet to place the “other” option before the 4th answer option (SQ004 - “Decline” -- in the example above).
Copy the following code and paste it into the Script panel in your question details (edit line #5 and replace SQ004 with your own relevant answer code):
/* Adjust these settings */
/* Please do NOT change the lines below */
Save your question, and preview it to confirm the Other option is in the desired location: