To answer this question, we need to identify the odd one out among the given options: Cat, Rat, Mat, and Bat.
Option A) Cat - This option is not the odd one out because it is a valid word.
Option B) Rat - This option is not the odd one out because it is a valid word.
Option C) Mat - This option is the odd one out because it does not represent an animal like the other options (Cat and Rat) or an object (Bat).
Option D) Bat - This option is not the odd one out because it is a valid word.
Therefore, the correct answer is C) Mat.