Question: In which format, introduced in 1948, was the album Showcase released in?

Context paragraphs:
DxO ONE: Introduced in June 2015, the DxO ONE from DxO Labs is a small camera that attaches to an iPhone or iPad using the Lightning connector port.  The DxO ONE has a 1-inch format, 20.2 megapixel image sensor—the same one that is found in the Sony Cyber-shot DSC-RX100—as well as an f/1.8 maximum-aperture lens and high-speed shutter.  The ONE uses the attached mobile device as an electronic viewfinder for the camera—which does not have its own viewfinder.  European Imaging and Sound Association awarded the DxO ONE its prize for photo innovation for 2015-2016.  DxO has also created a website where photographers can showcase images taken with the DxO ONE.

Sketchorama: Sketchorama is a radio show, a product of The Comedy Unit, commissioned by the BBC for Radio 4.  It features a rotating cast of comedic sketch groups who perform in front of a live audience.  The groups are introduced by a host comedian, originally Humphrey Ker, now Thom Tuck.  The show is currently in its third season.  The British Comedy Guide describes it as "a format for Radio 4 which offers the same popular showcase dynamic as stand-up shows, but purely for comedy sketch groups.  Sketchorama aims to bring hidden gems and established live acts to the airwaves offering a truly distinctive and ambitious show."

Sampler album: A sampler is a type of compilation album generally offered at a reduced price to showcase a selection of artists signed to a particular record label.  The format became popular in the late 1960s as record labels sought to promote artists whose works were primarily available in album rather than single format, and therefore had little opportunity to gain exposure through singles-dominated radio airplay.  Most samplers showcased already-released material, so that as they sampled artists they also sampled the albums from which their tracks were drawn.

Showcase in a Suitcase: Showcase In A Suitcase is a reggae album comprising showcase (songs followed by dubs) format material produced by Prince Far I, and performed by Prince Far I, Ashanti Roy, The Wailing Souls, and Naggo Morris.  The backing band throughout is the Roots Radics.  The tracks on the album were taken from singles released on Prince Far I's Cry Tuff label, and remixed for inclusion on the album.  The album reached number six in the UK Reggae Chart published by "Sounds" in December 1980.

Showcase (Buddy Holly album): Showcase is a compilation album by American rock and roll singer Buddy Holly.  The album was released as an LP record in both mono and stereo formats in May 1964 (see 1964 in music).

Why I Sing the Blues: Why I Sing the Blues is a 1983 compilation album by the blues guitarist and singer B.B. King.  Originally made by MCA Records as a bargain-bin greatest hits compilation, the album is a showcase of King's best work from the late 1960s and early 1970s.  The album was released in CD format in 1995.

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.  Introduced by Columbia in 1948, it was soon adopted as a new standard by the entire record industry.  Apart from a few relatively minor refinements and the important later addition of stereophonic sound, it has remained the standard format for vinyl albums.

Opus Nocturne: Opus Nocturne is the third studio album by Swedish black metal band Marduk.  It was recorded and mixed at Hellspawn Studios in September 1994 and released that December by Osmose Productions.  It was re-released in digipak format that included bonus rehearsal tracks on June 27, 2006.  "Opus Nocturne" is the last Marduk album to feature Joakim Göthberg on vocals and Dan Swanö as mixer.  "Opus Nocturne" was the first album to showcase Marduk's signature hyper-speed blast beat tempo, however it still contained much of the melody from "Those of the Unlight" while retaining this break-neck speed, instead of sheer brutality on albums like "Heaven Shall Burn... When We Are Gathered" and "Nightwing".

Born to Sing the Blues: Born to Sing the Blues is Shirley Bassey's debut album, released on a 10" LP in 1957 by the Philips Records label.  Long-playing records were newly introduced in the mid-1950s and the 10" album was briefly introduced as an album format.  Within a few years, the 12" album was the format offered to the record buying public, remaining so until the mid-1980s when the Compact Disc took the market by storm.

Toni Gonzaga (album): Toni Gonzaga is an independent and the eponymous debut studio album under Prime Music Inc. released on July 26, 2002, in CD format only, in the Philippines.  All songs were recorded and mixed at Greenhill Sound Productions, Inc.  The album was not known in years due to loss of promotions and the difficulty for her to engage in bigger market, until Gonzaga herself given the chance to showcase her talent as a singer in late 2005 when she released her first commercial single, "We Belong".  However, "Hanggang Ngayon" was Gonzaga's first credit as a songwriter.

Supporting paragraphs: Showcase (Buddy Holly album) LP record
Answer: LP record