Which of these sentences is an example of allusion?
It is the safest thing you can do—Hark, again!—to get yourself thoroughly drenched in a thunder-storm.
Who has empowered you, you Tetzel, to peddle round your indulgences from divine ordinations?
Will you order one of my rods? Look at this specimen one? See: it is of the best of copper. Copper's the best conductor.
Briefly, then. I avoid pine-trees, high houses, lonely barns, upland pastures, running water, flocks of cattle and sheep, a crowd of men.

Question

Which of these sentences  is an example of allusion?
It is the safest thing you can do—Hark, again!—to get yourself thoroughly drenched in a thunder-storm.
Who has empowered you, you Tetzel, to peddle round your indulgences from divine ordinations?
Will you order one of my rods? Look at this specimen one? See: it is of the best of copper. Copper's the best conductor.
Briefly, then. I avoid pine-trees, high houses, lonely barns, upland pastures, running water, flocks of cattle and sheep, a crowd of men.