Question: Name the carbon-containing flammable gas with the lowest standard enthalpy of formation ?
Paraphrase: What is the name of the carbon-containing gas that has the lowest standard enthalpy of formation?
SPARQL (Wikidata): select ?ent where { ?ent wdt:P31 wd:Q21073026 . ?ent wdt:P3078 ?obj . ?ent wdt:P527 wd:Q623. } ORDER BY ASC(?obj)LIMIT 5