Information: - In physics, sound is a vibration that propagates as a typically audible mechanical wave of pressure and displacement, through a transmission medium such as air or water. In physiology and psychology, sound is the "reception" of such waves and their "perception" by the brain. Humans can hear sound waves with frequencies between about 20Hz and 20kHz. Sound above 20kHz is ultrasound and below 20Hz is infrasound. Other animals have different hearing ranges. - A chordophone is a musical instrument that makes sound by way of a vibrating string or strings stretched between two points. It is one of the four main divisions of instruments in the original Hornbostel-Sachs scheme of musical instrument classification. - Vietnam, officially the Socialist Republic of Vietnam (SRV), is the easternmost country on the Indochina Peninsula in Southeast Asia. With an estimated 90.5 million inhabitants , it is the world's 14th-most-populous country, and the eighth-most-populous Asian country. Vietnam is bordered by China to the north, Laos to the northwest, Cambodia to the southwest, Thailand across the Gulf of Thailand to the southwest, and the Philippines, Malaysia and Indonesia across the South China Sea to the east and southeast. Its capital city has been Hanoi since the reunification of North and South Vietnam in 1976. - A fingerpick is a type of plectrum used most commonly for playing bluegrass style banjo music. Most fingerpicks are composed of metal or plastic. Unlike flat guitar picks, which are held between the thumb and finger and used one at a time, fingerpicks clip onto or wrap around the end of the fingers and thumb; thus one hand can pick several strings at once. Generally three are used: one for the thumb, and one each for the middle and index fingers. Fingerpicks worn on the thumb are generally called "thumbpicks". Most players use a plastic thumbpick while using metal fingerpicks. Fingerpicks come in a variety of thicknesses to accommodate different musicians' styles of playing. Thin picks produce a quieter, more delicate sound, while thick picks produce a heavier sound. - Zither (or ) is a class of stringed instruments. - Ivory is a hard, white material from the tusks (traditionally elephant's) and teeth of animals, that can be used in art or manufacturing. It consists mainly of dentine (inorganic formula Ca(PO)(CO)HO)), one of the physical structures of teeth and tusks. The chemical structure of the teeth and tusks of mammals is the same, regardless of the species of origin. The trade in certain teeth and tusks other than elephant is well established and widespread; therefore, "ivory" can correctly be used to describe any mammalian teeth or tusks of commercial interest which are large enough to be carved or scrimshawed. It has been valued since ancient times for making a range of items, from ivory carvings to false teeth, fans, and dominoes. Elephant ivory is the most important source, but ivory from mammoth, walrus, hippopotamus, sperm whale, killer whale, narwhal and wart hog are used as well. Elk also have two ivory teeth, which are believed to be the remnants of tusks from their ancestors. - The yatug (Mongolian: yatug-a, Khalkha dialect: yatga Chinese: ) is a traditional Mongolian plucked zither, related to the Chinese "guzheng". Yatga may vary widely in size, tuning, and number of bridges and strings; The body is a long wooden box, one end of which is angled downward. The performer plucks the strings with the fingernails of the right hand; the left hand is used to put pressure on the strings, varying the note. The left hand can also be used to play the bass strings without plectrums (picks). Depending on style the higher strings are picked by fingers or by picks. - In polymer chemistry and materials science, resin is a "solid or highly viscous substance" of plant or synthetic origin that is typically convertible into polymers. They are often mixtures of organic compounds, principally terpenes. Many plants, particularly woody plants, produce resin in response to injury. The resin acts as a bandage protecting the plant from invading insects and pathogens. - The guzheng, also known as the Chinese zither, is a Chinese plucked string instrument with a more than 2,500-year history. It has 16 (or more) strings and movable bridges. The modern "guzheng" usually has 21 strings, and is long. It has a large, resonant cavity made from "wutong" wood. Other components are often made from other woods for structural or decorative reasons. "Guzheng" players often wear fingerpicks, made from materials such as ivory, tortoise shell, resin or hard plastic, on one or both hands. - The an tranh () is a plucked zither of Vietnam, which is similar to the Chinese "guzheng" , the Japanese "koto", the Korean "kayagum" and the Mongolia "Yatga". In northern Vietnam, the instrument is also known as the an thp lc. It has a long soundbox with the steel strings, movable bridges and tuning pegs positioned on its top. - String instruments, stringed instruments, or chordophones are musical instruments that produce sound from vibrating strings when the performer plays or sounds the strings in some manner. - Mongolia (Mongolian: ["Monggol Ulus"] in Mongolian script; ["Mongol Uls"] in Mongolian Cyrillic) is a landlocked unitary sovereign state in East Asia. Its area is roughly equivalent with the historical territory of Outer Mongolia, and that term is sometimes used to refer to the current state. It is sandwiched between China to the south and Russia to the north. While it does not share a border with Kazakhstan, Mongolia is separated from it by only . - The gayageum or kayagum is a traditional Korean zither - like string instrument , with 12 strings , though some more recent variants have 21 or other number of strings . It is probably the best known traditional Korean musical instrument . It is related to other Asian instruments , including the Chinese guzheng , the Japanese koto , the Mongolian yatga , and the Vietnamese an tranh . Given the information above, choose from the list below the object entity that exhibits the relation 'subclass of' with the subject 'gayageum'. Choices: - bass - border - box - capital - chinese - chordophone - city - class - country - dialect - injury - insects - japanese - korean - manufacturing - materials science - mongolian - music - musical - musical instrument - note - number - performer - physics - physiology - plant - plucked string instrument - polymer - psychology - range - republic - resin - scheme - shell - sound - sovereign state - species - state - steel - structure - style - term - territory - trade - type - whale - white - wood - zither
A:
plucked string instrument