question: fish:scales
choices.label: A B C D
choices.text: man:clothes bird:feather books:table of contents silkworm:cocoon
explanation: "scales" are part of a "fish", and a "fish" is an animal. "men" need "clothes" to cover their bodies. "feathers" are part of "birds", and "birds" are animals. the "table of contents" is part of a "book", but a "book" is not an animal. the protective layer of the pupal stage of "silkworm" is "cocoon".
relation: fish scales R2.3
relation: man clothes R3.10
relation: silkworm cocoon R3.10