Read this and answer the question. If the question is unanswerable, say "unanswerable".

Beginning in 1939, Dr. Peter Goldmark and his staff at Columbia Records and at CBS Laboratories undertook efforts to address problems of recording and playing back narrow grooves and developing an inexpensive, reliable consumer playback system. It took about eight years of study, except when it was suspended because of World War II. Finally, the 12-inch (30 cm) Long Play (LP) 33 1⁄3 rpm microgroove record album was introduced by the Columbia Record Company at a New York press conference on June 18, 1948.

On what date was the 12 inch LP released?
June 18, 1948