Question: In which format did this type of music retail outlet, such as Bull Moose Music, sell music?
Context: "I Can't Go on Without You" is a 1948 song by Bull Moose Jackson and His Buffalo Bearcats.  The single was Bull Moose Jackson most successful release on the R&B chart reaching number one for eight weeks. The Progressive Party of 1912 was an American third party.  It was formed by former President Theodore Roosevelt after he lost the presidential nomination of the Republican Party to his former protégé, President William Howard Taft.  The new party was known for taking advanced positions on progressive reforms and attracting some leading reformers.  After the party's defeat in the presidential election, the party went into rapid decline, disappearing by 1918.  The Progressive party was nicknamed the "Bull Moose Party" after journalists quoted Roosevelt saying that he felt "fit as a bull moose" following an assassination attempt on the campaign trail shortly after the new party was formed. Amazon Music (previously Amazon MP3) is a music streaming platform, online music store, and music locker operated by Amazon.com.  Launched in public beta on September 25, 2007, in January 2008 it became the first music store to sell music without digital rights management (DRM) from the four major music labels (EMI, Universal, Warner Music, and Sony BMG), as well as many independents.  All tracks were originally sold in 256 kilobits-per-second variable bitrate MP3 format without per-customer watermarking or DRM; however, some tracks are now watermarked.  Licensing agreements with recording companies restrict the countries in which music can be sold: Amazon.com sells music only to US customers while Amazon.co.uk sells music only to UK customers. Bull Moose is an independent retailer and record store chain based in Portland, Maine, USA.  The chain has operated since 1989 and has nine locations in Maine and three in New Hampshire.  It has been featured in various newspapers throughout Maine and New Hampshire.  It was founded by Brett Wickard in Brunswick, Maine in 1989, though he did not file it as a Business Corporation until 1995.  Bull Moose was started with $37,000.  Chris Brown was hired in 1991 as a clerk and later became the creator of Record Store Day, and the company's Vice President. Planet M is an Indian music retail store founded by The Times Group (BCCL).  It was sold to Next Retail India Ltd. of Mumbai, the retail arm of Videocon, in November 2007.  It is present in many cities (140-plus locations) all over India.  These stores are mainly known for selling music and movies and related accessories.  They also sell gaming consoles and handhelds like PlayStation Portable, PS2, PS3, Wii and Xbox 360.  Planet M is also a new entrant in the mobile retail business.  They offer a wide range of mobile handsets with lucrative schemes. Benny Kay is an American recording artist and award-winning producer who has been creating music for over thirty years.  Kay began his career in music by playing blues and barrelhouse piano at coffeehouses in the Boston, Massachusetts area.  He became known for recording a risque version of Louis Armstrong's "Cheesecake", and appeared several times on the Joel "Fats" Rogers Show on WBCN in Boston.  Kay recorded his first album for the Aladdin Records label, at the age of eighteen, serving as piano player for the seven-piece rhythm and blues band, Powerhouse.  Among the highlights of the initial and subsequent Powerhouse releases are guest performances by Bull Moose Jackson and guitarist J. Geils.  Over several years of regional touring with Powerhouse, Kay performed with or opened for Bonnie Raitt, Muddy Waters, James Cotton, Big Walter Horton, J. B. Hutto, John Lee Hooker, Frank Zappa, Captain Beefheart, Blood Sweat & Tears, NRBQ, Bob Margolin, Janis Ian, The Nighthawks and many others. Bull Moose Township is a township in Cass County, Minnesota, United States.  The population was 107 as of the 2000 census.  This township was named after the Bull Moose Party. Booth's Music is a music retail outlet in the oldest part of Bolton town centre, Churchgate, UK.  The store sells sheet music, instruments and accessories and offers music tuition and repairs and servicing to instruments.  It also features a recording studio. A record shop or record store is a retail outlet that sells recorded music.  In the late 19th century and the early 20th century, record shops only sold gramophone records, but over the 20th century, record shops sold the new formats that were developed, such as eight track tapes, compact cassettes and compact discs (CDs).  Today in the 21st century, record stores sell CDs, vinyl records and in some cases, DVDs of movies, TV shows, cartoons and concerts.  Some record stores also sell music-related items such as posters of bands or singers and even clothing and items such as bags and coffee mugs. Being angry at their candidate being robbed of the 1912 Republican presidential nomination they thought was rightfully his, Supporters of former President Theodore Roosevelt convened in Chicago and endorsed the formation of a national progressive party.  When formally launched later that summer, the new Progressive Party acclaimed Roosevelt as its presidential nominee and Governor Hiram Johnson of California as his running mate.  Questioned by reporters, Roosevelt said he felt as strong as a "bull moose."  Henceforth known as the "Bull Moose Party," the Progressives promised to increase federal regulation and protect the welfare of ordinary people.
Answer: gramophone records