Question: What are the psychoactive which start with the letter o
Paraphrase: What are the psychoactive which begin  with the letter o
SPARQL (Wikidata): SELECT DISTINCT ?sbj ?sbj_label WHERE { ?sbj wdt:P31 wd:Q3706669 . ?sbj rdfs:label ?sbj_label . FILTER(STRSTARTS(lcase(?sbj_label), 'o')) . FILTER (lang(?sbj_label) = 'en') } LIMIT 25 
Answer: opium, opium