Question: Which is extinct, the Russian tracker or Norfolk Terrier.?

Context paragraphs:
Norfolk boobook: The Norfolk boobook ("Ninox novaeseelandiae undulata"), also known as the Norfolk Island boobook, Norfolk Island owl or Norfolk Island morepork, was a bird in the true owl family endemic to Norfolk Island, an Australian territory in the Tasman Sea between Australia and New Zealand.  It is an extinct subspecies of the morepork ("Ninox novaeseelandiae").  However, although the taxon is extinct, its genes live on in the descendants of the hybrid offspring of the last female bird, which was sighted for the last time in 1996.

Russian tracker: The Russian Tracker or Russian Retriever is an extinct breed of domestic dog.  It is uncertain when precisely the breed ceased to exist; it could still be found in the late 1800s.  The Tracker was of Asiatic Russian origin.  It was used for hundreds of years to protect and herd the flocks of the Indo-Aryan people in the wind-beaten, snow-swept Caucasus Mountains.

Paisley Terrier: The Paisley Terrier was a breed of terrier type dog that is now extinct.  Originating in Scotland, the Paisley Terrier was bred primarily as a pet and showdog version of the Skye Terrier, and was the progenitor of today's Yorkshire Terrier.  The breed was called the Paisley terrier since most of the dogs came from that location, but it was also called the Clydesdale Terrier, for another location in the Clyde Valley where the dogs were bred.

Russkiy Toy: The Russian Toy (also known as the Russian Toy Terrier, and in Russia as the Russkiy Toy, Toychik,Russian: Русский той, Тойчик ) is a very small breed of dog originally bred in Russia from the English Toy Terrier which is known today as the Manchester Terrier.  There are two types of coats in the breed: smooth coat and long coat.  The smooth-coated variety was previously known as the Russian Toy Terrier and long-coated as the Moscow Long Haired Toy Terrier.  Both were brought together under the same Russian Toy Terrier name in 1988 and the "Terrier" was dropped from the name when the breed was added in 2006 to the official list of breeds registered with the Fédération Cynologique Internationale and has been registered in the Foundation Stock Service of the American Kennel Club since 2008, allowed to compete in AKC companion events since 2010.  The first official breed standard of the two varieties was written in 1966 in Russia.

Feist (dog): A Feist is a small hunting dog, descended from the terriers brought over to the United States by English miners and other working class immigrants.  These terriers probably included crosses between the Smooth Fox Terrier, the Manchester Terrier and the now extinct English White Terrier.  These dogs were used as ratters, and gambling on their prowess in killing rats was a favorite hobby of their owners.  Some of these dogs have been crossed with Whippets or Italian Greyhounds (for speed) and Beagles (for hunting ability) - extending the family to include a larger variety of purpose than the original ratter, or Rat Terrier.

Teddy Roosevelt Terrier: The Teddy Roosevelt Terrier is a small to medium-sized American hunting terrier.  Lower-set with shorter legs, more muscular, and heavier bone density than its cousin the American Rat Terrier.  There is much diversity in the history of the Teddy Roosevelt Terrier breed and it shares a common early history with the American Rat Terrier, Fox Paulistinha and Tenterfield Terrier.  It is said the Rat Terrier background stems from the terriers or other dogs that were brought over by early English and other working class immigrants.  Since the breed was a farm, hunting and utility dog there was little to no planned breeding other than breeding dogs with agreeable traits to each other in order to produce the desired work ethic in the dog.  It is assumed that the Feist (dog), Bull Terrier, Smooth Fox Terrier, Manchester Terrier, Whippet, Italian Greyhound, the now extinct English White Terrier, Turnspit dog and or Wry Legged Terrier all share in the Teddy Roosevelt Terrier's ancestry.  These early Ratting Terriers were then most likely bred to the Beagle or Beagle cross bred dogs (for increased scenting ability) and other dogs.  Maximizing the influences from these various breeds provides the modern Teddy Roosevelt Terrier with a keen sense of awareness and prey drive, an acute sense of smell and a very high intellect.  Although they tend to be aloof with strangers they are devoted companion dogs with a strong desire to please and be near their owners side at all times.

English White Terrier: The English white terrier (also known as the White English terrier or Old English terrier) is an extinct breed of dog.  The English White terrier is the failed show ring name of a pricked-ear version of the white fox-working terriers that have existed in Great Britain since the late 18th Century.

Norwich Terrier: The Norwich Terrier is a breed of dog originating in the United Kingdom, and was bred to hunt small vermin or rodents.  With a friendly personality, Norwich Terriers are today mostly a companion dog breed.  One of the smallest terriers, these dogs are generally healthy, but are relatively rare, due in part to their low litter size and the common need for caesarian sections.  Their drop-eared variety is the Norfolk Terrier.

Norfolk Terrier: The Norfolk Terrier is a British breed of dog.  Prior to gaining recognition as an independent breed in 1964, it was a variety of the Norwich Terrier, distinguished from the "prick eared" Norwich by its "drop ears" (or folded ears).  Together, the Norfolk and Norwich Terriers are the smallest of the working terriers.

Airedale Terrier: The Airedale Terrier (often shortened to "Airedale"), also called Bingley Terrier and Waterside Terrier, is a dog breed of the terrier type that originated in the valley ("dale") of the River Aire, in the West Riding of Yorkshire, England.  It is traditionally called the "King of Terriers" because it is the largest of the terrier breeds.  The Airedale was bred from the Old English Black and Tan Terrier (now extinct), the Bull Terrier, the Otterhound and probably some other Terrier breeds, originally to serve as an all around working farm dog.  In Britain this breed has also been used as a war dog, guide dog and police dog.  In the United States, this breed has been used to hunt big game, upland birds, and water fowl, and serve in many other working capacities.

Supporting paragraphs: Russian tracker Norfolk Terrier
Answer: Russian Tracker