Question: In which format, introduced in 1948, was the album Showcase released in?
Sentence (from "LP record"): The LP (from "long playing" or "long play") is an analog sound storage medium, a vinyl record format characterized by a speed of 33 ⁄ rpm, a 12 or 10 inch (30 or 25 cm) diameter, and use of the "microgroove" groove specification.
Relevant evidence: No