Information:  - The First Sea Lord and Chief of Naval Staff (1SL/CNS) is the professional head of the United Kingdom's Royal Navy and the whole Naval Service; originally the title was the First Naval Lord. The concept of a professional "First Naval Lord" was introduced in 1805, and the title of the First Naval Lord was changed to "First Sea Lord" on the appointment of Sir Jackie Fisher in 1904. From 1923 onward, the First Sea Lord was a member of the Chiefs of Staff Committee; he now sits on the Defence Council and the Admiralty Board.  - Patricia Edwina Victoria Knatchbull , 2nd Countess Mountbatten of Burma , Dowager Lady Brabourne , CBE , MSC , CD , JP , DL ( born 14 February 1924 ) is a British peer and the third cousin of Queen Elizabeth II. She is the elder daughter of Louis Mountbatten , 1st Earl Mountbatten of Burma and his wife , the heiress Edwina Ashley , a patrilineal descendant of the Earls of Shaftesbury , first ennobled in 1661 . She is the elder sister of Lady Pamela Hicks , and first cousin to Prince Philip , Duke of Edinburgh . Mountbatten succeeded her father when he was assassinated in 1979 , as his peerages had been created by the Crown with special remainder to his daughters and their heirs male . This inheritance accorded her the title of countess and a seat in the House of Lords , where she remained until 1999 , when the House of Lords Act 1999 removed most hereditary peers from the House .  - Admiral of the Fleet Louis Francis Albert Victor Nicholas Mountbatten, 1st Earl Mountbatten of Burma, (born Prince Louis of Battenberg; 25 June 1900  27 August 1979), known informally as Lord Mountbatten, was a British naval officer and statesman, an uncle of Prince Philip, Duke of Edinburgh, and second cousin once removed of Elizabeth II. During the Second World War, he was Supreme Allied Commander, South East Asia Command (194346). He was the last Viceroy of India (1947) and the first Governor-General of the independent Dominion of India (194748), from which the modern Republic of India emerged in 1950. From 1954 until 1959 he was First Sea Lord, a position that had been held by his father, Prince Louis of Battenberg, some forty years earlier. Thereafter he served as Chief of the Defence Staff until 1965, making him the longest serving professional head of the British Armed Forces to date. During this period Mountbatten also served as Chairman of the NATO Military Committee for a year.    After reading the paragraphs above, we are interested in knowing the entity with which 'patricia knatchbull' exhibits the relationship of 'military branch'. Find the answer from the choices below.  Choices: - naval service  - royal navy
Answer:
royal navy