Which of the following was used in the United States in the late 1800s to
depict Chinese immigrants as the cause of economic problems?

The right answer is 4: by using only rhyming words that have an equivalent number of syllables. This is an example:

"What the hammer? what the chain?

In what furnace was thy brain?

What the anvil? what dread grasp

Dare its deadly terrors clasp?"

Chain and brain, as well as grasp and clasp, are pairs of words that rhyme and have the same number of syllables (cha-in, bra-in, grasp and clasp). This pattern is used by the author at the end of every verse throughout the poem.