Concept:A paradox joins contradictory or impossible ideas in order to express a deeper truth.
Explanation:Blake says a world can be seen inside a grain of sand and heaven within a wild flower.
He also says infinity can be held in the palm of a hand and eternity within a single hour.
These images are impossible in a literal sense, because a grain of sand is tiny while a world is vast.
In the same way, an hour is fleeting, but eternity has no end.
By placing these opposite ideas side by side, Blake creates a paradox.
His meaning is that the infinite can be glimpsed through the smallest and most ordinary things.
This is not a simile, because there is no comparison using "like" or "as".
It is not chiefly hyperbole, because the lines express a serious underlying truth rather than mere exaggeration.
Therefore, the predominant figure of speech in the lines is paradox.
Answer:C. paradox