Question: The 24-hour music format produced by Dial Global Networks includes music from which band formed in London in 1968?

Context paragraphs:
Country Classics: Classic Country (Local Version) (formerly known as Country Classics was a 24-hour music format produced by Dial Global, formerly by Waitt Radio Networks and then by Dial Global's Dial Global Local division.  Its playlist is composed of classic country music released from the 1970s to the 1990s by artists such as Willie Nelson, Waylon Jennings, Dolly Parton, Reba McEntire, Kenny Rogers, etc. that mainly targets listeners ages 35-54.

AC Pure: AC Pure was a 24-hour music format produced by Waitt Radio Networks and then by Dial Global under its Dial Global Local banner.  Its playlist was composed of adult contemporary music released from the 1970s to this day from artists such as Phil Collins, Celine Dion, Rod Stewart Gloria Estefan, Michael Bolton, etc. that mainly targeted listeners ages 25-54.

Rock 2.0: Rock 2.0, formerly Modern Rock, is a 24-hour music format produced by the Dial Global Radio Networks, and formerly distributed through its now-defunct Dial Global Local service.  Its playlist is composed of highly tested classic rock from the 1980s combined with alternative and active rock music released from the 1990s to this day from artists such as Red Hot Chili Peppers, Nirvana, Nickelback, Pearl Jam, Metallica, etc.  This satellite/internet-driven programming service predominantly targets male listeners in the 18-44 demographic range with a 20- to 40-year-old target.

Led Zeppelin: Led Zeppelin were an English rock band formed in London in 1968.  The group consisted of guitarist Jimmy Page, singer Robert Plant, bassist and keyboardist John Paul Jones, and drummer John Bonham.  The band's heavy, guitar-driven sound has led them to be cited as one of the progenitors of heavy metal, though their unique style drew from a wide variety of influences, including blues, psychedelia, and folk music.

True Country: True Country is an American 24-hour music format produced by Dial Global Networks.  Its playlist is composed of a diverse mix of classic and some handpicked modern country music from artists such as Randy Travis, Garth Brooks, Martina McBride, Alabama, Trace Adkins, Brad Paisley and dozens more artists.

Hits Now!: Hits Now!  is a 24-hour music format produced by Dial Global.  Its playlist is composed of mostly Top 40 (CHR) music from artists such as Rihanna, Katy Perry, Taylor Swift, Bruno Mars, Ke$ha, The Black Eyed Peas, and Usher among others, that mainly targets listeners ages 18–49.  Hits Now!  is the only 24-hour CHR/Top 40 music format currently offered via satellite in the United States; Cumulus Media offers a Hot AC format, and Dial Global offers two (one Total and one Local).  However, ABC Radio offered a satellite-delivered CHR format in the early 1990s called "The Heat."

Genuine Classic Rock: Classic Rock (Local Version) (formerly known as Genuine Classic Rock) is a 24-hour music format produced by Dial Global, formerly by Waitt Radio Networks and then by the now-defunct Dial Global Local.  Its playlist comprises classic rock music released from the 1960s to the 1980s from artists such as ZZ Top, Led Zeppelin, Aerosmith, Pink Floyd, Lynyrd Skynyrd, Tom Petty and Eric Clapton among others.

The Lounge (radio network): The Lounge was a 24-hour music network produced by Dial Global and distributed under their Dial Global Local brand (formerly by Waitt Radio Networks).  The network's tag line was Great Songs and Stars.  The format was discontinued on June 17, 2012, as part of a corporate reorganization by Dial Global which resulted in the elimination of the Dial Global Local brand and the absorption of most of the other DG Local formats into the main Dial Global portfolio.

Country Today: Mainstream Country (Local Version) (formerly known as Country Today) is a 24-hour music format produced by Dial Global, and formerly by Waitt Radio Networks and then by the now-defunct Dial Global Local.  Its playlist is composed of country music released from the 1990s through the present from artists such as Tim McGraw, Carrie Underwood, George Strait, Lady Antebellum, Kenny Chesney, etc. that mainly targets listeners in the mainstream demographic area ages 18–34 and 25-44 in the active country demographic range.

Classic Rock (Dial Global radio network): Classic Rock (formerly Rock Classics) is a 24-hour music format produced by Dial Global Networks.  Its playlist consists mostly of contemporary classic rock music from artists such as Led Zeppelin, Pink Floyd, Lynyrd Skynyrd and Van Halen, The Rolling Stones.  The format was launched in July 1997 by Jones Senior Director of Programming Jon Holiday and has been programmed by Adam Fendrich since 2001.

Supporting paragraphs: Classic Rock (Dial Global radio network) Led Zeppelin
Answer: Led Zeppelin