Question: What is the primary instrument played by the artist responsible for Waitin for the Sun?

Context paragraphs:
Ricky Skaggs: Rickie Lee Skaggs (born July 18, 1954), known professionally as Ricky Skaggs, is an American country and bluegrass singer, musician, producer, and composer.  He primarily plays mandolin; however, he also plays fiddle, guitar, mandocaster and banjo.

Aeolian harp: An Aeolian harp (also wind harp) is a musical instrument that is played by the wind.  Named for Aeolus, the ancient Greek god of the wind, the traditional Aeolian harp is essentially a wooden box including a sounding board, with strings stretched lengthwise across two bridges.  It is often placed in a slightly opened window where the wind can blow across the strings to produce sounds.  The strings can be made of different materials (or thicknesses) and all be tuned to the same pitch, or identical strings can be tuned to different pitches.  Besides being the only strung instrument played solely by the wind, the Aeolian harp is the only stringed instrument that plays solely harmonic frequencies.

Waitin' for the Sun to Shine: Waitin' for the Sun to Shine is the third studio album from Ricky Skaggs.  It was released in 1981 on Epic Records.  Skaggs himself produced the album, and played on all the songs.

Bowed dulcimer: The bowed dulcimer is a musical instrument.  Designed in the style of the Appalachian dulcimer (a fretted string instrument of the zither family, typically with three or four strings), it is either a standard instrument played with a violin bow, or a purpose-built dulcimer designed around bow playing.  The purpose-designed instrument is described as resembling a hybrid between a dulcimer and a cello or viola da gamba.

Double bell euphonium: The double bell euphonium is an instrument based on the euphonium.  The larger bell produces the mellow tone of a standard euphonium; the second smaller bell has a brighter tone, similar to a baritone horn or valve trombone.  The instrument is sometimes dismissed as a novelty, but has had a small number of enthusiastic adherents, although few professional musicians use it as their sole or primary instrument.  The smaller bell can give more appropriate tone in the higher range of the instrument.  The two bells can also be used for special effects, such as echoes, and using the distinctly different tone of the two bells for a single musician to give the effect of call and response.

Qanun (instrument): The kanun, ganoun or kanoon (Arabic: قانون‎ , "qānūn " ‎ ; Hebrew: קָנוֹן‎ , "qanon"; Persian: ‎ ‎ , "qānūn"; Turkish: "kanun" ; Armenian: քանոն , "k’anon " ; Azerbaijani: "qanun" ; Greek: κανονάκι , "kanonaki " ; Uyghur: قالون ‎, ULY: "qalon" ) is a string instrument played either solo, or more often as part of an ensemble, in much of the Middle East, Maghreb, West Africa, Central Asia, and southeastern regions of Europe.  The name derives from the Arabic word "qanun", meaning "rule, law, norm, principle", which is borrowed from the ancient Greek word and musical instrument (rule), which in Latin was called canon (not to be confused with the European polyphonic musical style and composition technique known by the same name).  Traditional and Classical musics executed on the qanun are based on Maqamat or Makamlar.  As the historical relative of santur from the same geography, qanun is thought to trace its origins back to Assyria, where an ancestral homologue might have been used in Mesopotamian royal courts and religious ceremonies.  The instrument today is a type of large zither with a thin trapezoidal soundboard that is famous for its unique melodramatic sound.

Primary instrument: A primary instrument is a scientific instrument, which by its physical characteristics is accurate and is not calibrated against anything else.  A primary instrument must be able to be exactly duplicated anywhere, anytime with identical results.

Sakharam Rao: Sakha Rama Rao (Sakharam Rao) is an Indian musician credited with having re-introduced the south Indian chitravina (or "gotuvadyam") to the concert scene.  However, it was his father, Srinivasa Rao, who made the pioneering effort towards the reincarnation of the chitravina in modern times.  He was an ardent music lover and an amateur artiste himself.  He started experimenting with a slide on the tanpura (a four-stringed instrument, usually used as a reference drone in Indian music).  Sakha Rama Rao was drawn to this instrument since childhood.  He was able to perceive its tremendous potential to produce high-class music.  He re-designed this instrument as a fretless veena with its usual set of seven strings - four strings on the top and three in the side for drone and rhythm.  He put in arduous practice on this instrument and gave occasional performances.  Since he was not aware of the history of the instrument, he gave it a new name - gotuvadyam.  This is because, he used to casually refer to the slide as 'gotu'.  'Vadyam', in Sanskrit and many other Indian languages, means instrument.  Thus, 'gotuvadyam' was a literal name for an instrument played with a slide.  Several decades later, Ravikiran, along with a few other scholars, studied about the origins of the instrument and eventually restored the more traditional name, chitravina.  Sakha Rama Rao was a "musicians' musician" and trained many great artists like Gotuvadyam Narayana Iyengar and Semmangudi Srinivasa Iyer.  Soon there were several others who started performing on the chitravina (gotuvadyam).

Tonkori: The tonkori (トンコリ ) is a plucked string instrument played by the Ainu people of Hokkaidō, northern Japan and Sakhalin.  It generally has five strings, which are not stopped or fretted but simply played "open".  The instrument is believed to have been developed in Sakhalin.  By the 1970s the instrument was practically extinct, but is experiencing a revival along with the increased interest in Ainu heritage.

Unpitched percussion instrument: An unpitched percussion instrument is a percussion instrument played in such a way as to produce sounds of indeterminate pitch, or an instrument normally played in this fashion.

Supporting paragraphs: Waitin' for the Sun to Shine Ricky Skaggs
Answer: mandolin