Q:Information: - Motor Gun Boat ( MGB ) was a Royal Navy term for a small military vessel of the Second World War . Such boats were physically similar to Motor Torpedo Boats , ( MTBs ) but equipped with a mix of guns instead of torpedoes . Their small size and high speed made them difficult targets for E-boats or torpedo bombers , but they were particularly vulnerable to mines and heavy weather . The large number of guns meant the crew was relatively large , numbering as high as thirty men . In the early years of the war , they saw action defending shipping against enemy torpedo boats such as the German E-boats on the southern and eastern coasts of the UK . MGBs were also involved in the protection of shipping after D - Day . In the Mediterranean , they were used offensively to sink Italian and German shipping . They were formed into flotillas which often operated alongside Motor Torpedo Boats ( or US PT boats ) and helped interdict supplies being sent from Italy to North Africa in 1943 . After this campaign , they moved northwards and assisted with the invasion of Sicily , Sardinia , Corsica and Elba . From island bases they patrolled along the western coast of Italy attacking small coastal ships and E-boats until mid- 1944 . As Italy was progressively liberated , certain flotillas , such as the 56th , were sent around to the Adriatic to assist partisans in the islands off Yugoslavia . They did not take the prefix HMS as they were only boats and instead used the prefix '' HMMGB '' on formal occasions . The crews generally referred to them by their numbers . In 1947 , MGB 2009 was fitted with a Metrovick gas turbine , thereby becoming the world 's first gas turbine powered naval vessel . - The term warhead refers to the explosive or toxic material that is delivered by a missile, rocket, or torpedo. - The Royal Navy (RN) is the United Kingdom's naval warfare force. Although warships were used by the English kings from the early medieval period, the first major maritime engagements were fought in the Hundred Years War against the kingdom of France. The modern Royal Navy traces its origins to the early 16th century; the oldest of the UK's armed services, it is known as the Senior Service. - The modern torpedo is a self-propelled weapon with an explosive warhead, launched above or below the water surface, propelled underwater towards a target, and designed to detonate either on contact with its target or in proximity to it. - The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a sovereign country in western Europe. Lying off the north-western coast of the European mainland, it includes the island of Great Britain (the name of which is also loosely applied to the whole country), the north-eastern part of the island of Ireland, and many smaller islands. Northern Ireland is the only part of the UK that shares a land border with another sovereign statethe Republic of Ireland. Apart from this land border, the UK is surrounded by the Atlantic Ocean, with the North Sea to its east, the English Channel to its south and the Celtic Sea to its south-south-west, giving it the 12th-longest coastline in the world. The Irish Sea lies between Great Britain and Ireland. With an area of , the UK is the 78th-largest sovereign state in the world and the 11th-largest in Europe. It is also the 21st-most populous country, with an estimated 65.1 million inhabitants. Together, this makes it the fourth most densely populated country in the European Union. - Motor Torpedo Boat (MTB) was the name given to fast torpedo boats by the Royal Navy and the Royal Canadian Navy. The 'motor' in the formal designation, referring to the use of petrol engines, was to distinguish them from the majority of other naval craft that used steam turbines or reciprocating steam engines. - A torpedo boat is a relatively small and fast naval ship designed to carry torpedoes into battle. The first designs rammed enemy ships with explosive spar torpedoes, and later designs launched self-propelled Whitehead torpedoes. They were created to counter battleships and other slow and heavily armed ships by using speed, agility, and the power of their torpedo weapons. A number of inexpensive torpedo boats attacking en masse could overwhelm a larger ship's ability to fight them off using its large but cumbersome guns. An inexpensive fleet of torpedo boats could pose a threat to much larger and more expensive fleets of capital ships, albeit only in the coastal areas to which their small size and limited fuel load restricted them. After reading the paragraphs above, we are interested in knowing the entity with which 'motor gun boat' exhibits the relationship of 'subclass of'. Find the answer from the choices below. Choices: - country - fourth - lying - material - name - naval ship - navy - ocean - republic - rocket - sea - sovereign state - surface - term - torpedo - war - warfare - water - weapon - western - world
A:
naval ship