What does Chavez mean when he says the current labor system was a system of “economic slavery”?

What effect do the stanzas have on the meaning of this poem? a) each stanza asks the same question in different words. b) the stanzas do not work together to create meaning in the poem. c) each stanza presents a different aspect of the creation of the tiger. d) each stanza presents questions that are answered in the last stanza.