B

Impression compound is a low-fusing, reversible, thermoplastic material; it softens on heating and re-hardens on cooling, so it is not a thermoset. Because of its high coefficient of thermal expansion and low thermal conductivity it can warp as it cools to room temperature, and kneading with wet fingers increases its flow by incorporating water as a plasticizer. Therefore all the listed statements are true except that it “is a thermoset material.” [Wan Ali, 2021, PMID 34384124]