The correct answer is option C, which is, small. The root 'min' in the word 'diminish' means 'small'.
The root min in the word diminish means small.
It comes from Latin and is often used as a prefix or suffix in English words.
For example, the word minor means smaller or lesser.
Some other words that contain the root min are minute, minimum, and diminutive.
These words all have a similar meaning related to being small.
In the context of the word diminish, it means to make something smaller or reduce its size or importance.