PART B: Which phrase provides the best clue to the meaning of the word "ineffable"?

Ineffable means something great beyond words.

Explanation:

Calling something ineffable is almost like saying it is so great, so grand, or so extreme that there are no other words that could be used to describe it.

Effable can be used to refer to intellect, sense of humor, taste, and many other characteristics. A close synonym of ineffable, indescribable, is used in a similar way, but ineffable implies even more of a sense of greatness than indescribable.