In which format, introduced in 1948, was the album Showcase released in?
Showcase (Buddy Holly album): Showcase is a compilation album by American rock and roll singer Buddy Holly. Showcase (Buddy Holly album):  The album was released as an LP record in both mono and stereo formats in May 1964 (see 1964 in music). LP record:  Introduced by Columbia in 1948, it was soon adopted as a new standard by the entire record industry.
LP record