Question: "Best Of..." was a compilation almbum by which Australian singer-songwriter?
Context: The Very Best of Peter Allen is the first compilation album released by Australian singer-songwriter Peter Allen.  It was released in 1982 through A&M Records, completing the deal with the label.  The album peaked at number 9 on the Australian Kent Music Report.  . Best Of..., also referred to as Sia: Best Of..., is the first greatest hits album by Australian singer-songwriter Sia, released in Australia on 30 March 2012 through the Sydney-based independent record label Inertia.  The compilation includes tracks from four of her previous studio albums: "Healing Is Difficult" (2001), "Colour the Small One" (2004), "Some People Have Real Problems", (2008) and "We Are Born" (2010).  Also included are two tracks featuring Sia as a vocalist ("Destiny" by Zero 7 and "Titanium" by David Guetta), "My Love" from , plus a remixed version of "Buttons" by Brazilian rock band CSS. "Queen of Pop" is a compilation album album of songs recorded by on the Wizard Record label between 1975 and 1979 by Australian singer-songwriter Marcia Hines.  The album was released in November 2000 by BMG records. A compilation album comprises tracks, either previously released or unreleased, usually from several separate recordings by either one or several performers.  If by one artist, then generally the tracks were not originally intended for release together as a single work, but may be collected together as a greatest hits album or box set.  If from several performers there may be a theme, topic or genre which links the tracks, or they may have been intended for release as a single work - such as a tribute album.  When the tracks are by the same recording artist, the album may be referred to as a retrospective album.  Compilation albums may employ traditional product bundling strategies. Unconditional: Love Songs is the third compilation album released by Australian singer-songwriter Peter Andre, following "" (2002) and "The Platinum Collection" (2005). The discography of Guy Sebastian, an Australian singer-songwriter, consists of eight studio albums, one compilation album, one live album, three EPs and 34 singles, including three as a featured artist and four charity singles.  Sebastian won the first series of "Australian Idol" in 2003, and gained a record deal with Sony BMG.  He has released eight albums which peaked in the top six of the ARIA Charts, including two which reached number one.  The first seven achieved either platinum or multi-platinum certification.  He has also released twenty one top twenty singles in Australia, with twelve reaching the top ten, including six number ones.  Sebastian is the only Australian male artist in Australian chart history to achieve six number-one singles, and is third overall for all Australian acts with only Kylie Minogue and Delta Goodrem having achieved more.  He has also reached the top ten of the New Zealand charts with an album and six singles, including two number ones.  Sebastian has fifty-two platinum and seven gold certifications in Australia, the highest number for an "Australian Idol" contestant. " Battle Scars", a collaboration with Lupe Fiasco, spent 20 weeks in the "Billboard" Hot 100 chart, peaking at number 71 and achieving platinum certification.  It also reached number 2 in Norway. Amazing: The Best of Alex Lloyd is the first compilation album released in September 2006 by Australian singer-songwriter, Alex Lloyd. "Wiggle It" is a song performed by Australian singer-songwriter, Ricki-Lee Coulter.  It was co-written and co-produced by Coulter and Israel Cruz.  The song features additional rap vocals by Samir.  Released both physically and digitally on 13 September 2008 "Wiggle It" serves as the lead single from Coulter's compilation album, "". Best of the Soul Years is a 2015 compilation album by Australian singer-songwriter, Jimmy Barnes.  The album is compiled from his three platinum-selling albums of soul and R&B classics; "Soul Deep" (1991), "Soul Deeper... Songs from the Deep South" (2000) and "The Rhythm and the Blues" (2009).  The album also includes two new recordings, "In the Midnight Hour" and "Mustang Sally". Higher Than Hope is a compilation album by Australian singer-songwriter, Daryl Braithwaite released in United States of America and Europe in 1991.  The album includes the track "Higher Than Hope", which reached number 47 on the "Billboard" Hot 100.
Answer: Sia