Select the word that fits the analogy Do : Undo : : Trust : __________

The correct option is Distrust.

To solve this analogy, we need to examine the relationship between the first pair of words and apply the exact same relationship to the second pair.

Let's analyze the first pair: Do : Undo
The word "Undo" is the direct antonym (opposite) of "Do". It is formed by adding the prefix "un-" to the base word "do".

Now, we apply this same relationship to the second pair: Trust : __________
We need to find the antonym (opposite) of the word "Trust". While "un-" is a common prefix to make opposites, the standard opposite of "trust" in the English language is formed using the prefix "dis-", resulting in the word "Distrust".

Let's look at why the other options are incorrect:
- Intrust and Entrust: These are synonyms of trust (meaning to put into the care or protection of someone), not antonyms.
- Untrust: This is not a standard English word used as the direct opposite of trust.

Therefore, "Distrust" is the correct word that fits the analogy.