what is special about the 6, 5 and 4th ring?
Most inclined rings, and their orbital eccentricities are the largest excluding the ε ring.
Rings of Uranus
Rings 6, 5 and 4 are the innermost and dimmest of Uranus's narrow rings. They are the most inclined rings, and their orbital eccentricities are the largest excluding the ε ring. 
what is rings of uranus? Are intermediate in complexity between the more extensive set around Saturn and the simpler systems around Jupiter and Neptune. how many rings does this planet have? 13 when was the first time it was discovered? 1978 who discovered it? James L. Elliot, Edward W. Dunham, and Jessica Mink. where is the first person from? America apart from uranus has he discovered any other planets? Yes, discovered seven minor planets. and where is the third person from? Lincoln, Nebraska and has she also discovered anything else apart from the former planet? She did work that contributed to the discovery of the rings of Neptune. which tool was used to discover the rings? Kuiper Airborne Observatory
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Rings of Uranus [SEP] Rings 6, 5 and 4
Rings 6, 5 and 4 are the innermost and dimmest of Uranus's narrow rings. They are the most inclined rings, and their orbital eccentricities are the largest excluding the ε ring. In fact, their inclinations (0.06°, 0.05° and 0.03°) were large enough for "Voyager 2" to observe their elevations above the Uranian equatorial plane, which were 24–46 km. Rings 6, 5 and 4 are also the narrowest rings of Uranus, measuring 1.6–2.2 km, 1.9–4.9 km and 2.4–4.4 km wide, respectively. Their equivalent depths are 0.41 km, 0.91 and 0.71 km resulting in normal optical depth 0.18–0.25, 0.18–0.48 and 0.16–0.3. They were not visible during a ring plane-crossing event in 2007 due to their narrowness and lack of dust.