Question: It the breed of Galgo Español or The Estrela Mountain Dog used most often as a guard dog?
Context: The Maremma Sheepdog, in Italian Cane da pastore Maremmano-Abruzzese, is a breed of livestock guardian dog indigenous to central Italy, particularly to Abruzzo and the Maremma region of Tuscany and Lazio.  It has been used for centuries by Italian shepherds to guard sheep from wolves.  The literal English translation of the name is "The dog of the shepherds of the Maremma and Abruzzese region".  The English name of the breed derives from that of the Maremma marshlands, where until recently shepherds, dogs and hundreds of thousands of sheep over-wintered, and where the breed is today abundant although sheep-farming has decreased substantially.  The breed is widely employed in Abruzzo, where sheep herding remains vital to the rural economy and the wolf remains an active and protected predator.  Similar breeds include the Pyrenean Mountain Dog, the Kuvasz of Hungary, the Tatra of Poland, the Cuvac of Slovakia and the Šarplaninac (although not white), with all of which it may share a common ancestor; and the Akbash Dog of Turkey. A guard dog or watch dog (not to be confused with the attack dog) is a dog used to guard against, and watch for unwanted or unexpected people or animals.  The dog is discriminating so that it does not annoy or attack familiar people. The Bernese Mountain Dog (German: "Berner Sennenhund" ) is a large-sized breed of dog, one of the four breeds of Sennenhund-type dogs from the Swiss Alps.  The name "Sennenhund" is derived from the German "Senne" ("alpine pasture") and "Hund" ("dog"), as they accompanied the alpine herders and dairymen called "Senn".  "Berner" (or "Bernese" in English) refers to the area of the breed’s origin, in the canton of Bern.  This mountain dog was originally kept as a general farm dog.  Large Sennenhunde in the past were also used as draft animals, pulling carts.  The breed was officially established in 1907.  In 1937, the American Kennel Club recognized it; today, the club classifies it as a member of the Working Group. The Vanjari Hound (Malayalam: വഞ്ചാരി ഹൗണ്ട് ) is a breed of dog found in India.  It is a greyhound-type dog used by the nomadic Vanjari of Maharashtra, primarily as a sighthound in hunting.  However, it has also been used as a guard dog and a herding dog.  The breed is currently at risk from interbreeding with other dog breeds. The Mastín Español or Spanish Mastiff, is a giant breed of dog, originating in Spain, originally bred to be a guard dog whose specialized purpose is to be a Livestock guardian dog protecting flocks (and occasionally herds) from wolves and other predators.  The Mountain dog type has a heavier coat. The Kerry Blue Terrier (also known as the Irish Blue Terrier) () is a breed of dog.  Originally bred to control "vermin" including rats, rabbits, badgers, foxes, otters and hares, over time the Kerry became a general working dog used for a variety of jobs including herding cattle and sheep, and as a guard dog.  Today the Kerry has spread around the world as a companion and working dog.  Despite a Kerry Blue winning Crufts (the most important UK dog show) in 2000, it remains an "unfashionable" breed, and is distinctly uncommon; however, it not as threatened as some of the other terrier breeds such as Skye Terrier, Sealyham Terrier, and Dandie Dinmont Terrier. The Estrela Mountain Dog is a large breed of dog which has been used for centuries in the Estrela Mountains of Portugal to guard herds and homesteads. The Galgo Español ("Spanish galgo") or Spanish greyhound is an ancient breed of dog, specifically a member of the sighthound family. The Slovak Cuvac is a Slovak breed of dog, bred for use as a livestock guard dog.  This mountain dog—also known as Slovensky Cuvac, Slovak Chuvach, Tatransky Cuvac and Slovensky Kuvac—is closely related to the Hungarian Kuvasz.  The alternate German and English spelling "Tchouvatch" reflects the pronunciation: "chew-votch".  The breed is recognised under sponsorship from Slovakia by the Fédération Cynologique Internationale with the name Slovenský čuvač.  Despite the multiple renderings in English, these refer to only one breed.  The United Kennel Club in the US uses the English version of the name "Slovak Cuvac". Five ships of the Royal Navy have borne the name HMS "Galgo", after the Galgo Español, the Spanish greyhound:
Answer: Estrela Mountain Dog