premise: "Child labor" is, generally speaking, work for children that harms them or exploits them in some way (physically, mentally, morally, or by blocking access to education).
hypothesis: Child labor is terrible for children's well-being.
reason: Considering the context says "harms them or exploits them in some way (physically, mentally, morally, or by blocking access to education)," child labor being terrible for their well-being is definitely correct.