Question: Green Square railway station is located on the Airport line, serving which city suburb of Alexandria, a suburb in the inner-east of Sydney, New South Wales, Australia?

Context paragraphs:
Green Square railway station: Green Square railway station is located on the Airport line, serving the Sydney suburbs of Alexandria, Zetland, and Waterloo.  It is served by Sydney Trains T2 Airport line services.

Nanjing South Railway Station: The Nanjing South Railway Station () (IATA: NKJ) is a high-speed railway station in Nanjing, Jiangsu, People's Republic of China, serving the Jinghu High-Speed Railway, Huning Intercity Rail, Ninghang Passenger Railway and the Huhanrong (Shanghai–Wuhan–Chengdu) Railways.  The New Nanjing South Railway Station station is located a few kilometres south of downtown Nanjing.  The station's construction site is already connected with central Nanjing by Line 1, Line 3 and Line S1 of Nanjing Metro.  On September 30, 2016 the metro station served a peak volume of 102,300 passengers.  According to CCTV, it is the world's second largest railway station in terms of GFA (Gross Floor Area) at 458,000 square metre (4,929,871 square ft).  The dimension of the main roof is 456m x 216m (excluding smaller roof on both sides of the main roof), the main roof is constructed with steel weighing more than 8000 tons.  The roof on top of the waiting hall area (part of the main roof) is 72,000 square meter (775,001 square ft).  The entire railway station has 128 escalators, and 28 platforms (a combination of island-platforms and side-platforms).  At the peak of the construction phase, there were more than 20,000 construction workers and engineers at work.  Solar panels cover the majority of the railway station roof and are capable of providing 7.17 MW (megawatt) of electricity.

International Airport railway station, Sydney: International Airport railway station is located on the Airport line, serving Terminal 1 at Sydney Airport.  It is served by Sydney Trains T2 Airport line services.

Airport Link Company: The Airport Link Company operates Green Square, Mascot, Domestic Airport and International Airport railway stations on the T2 Airport & South line in Sydney, Australia.  These stations are located in the nine kilometre Airport line, which is 23 metres below the earth’s surface.  This tunnel links Sydney Airport with Central station and the Sydney central business district.

Macarthur railway station: Macarthur railway station is located on the Main South line, serving the Sydney suburb of Campbeltown.  It is served by Sydney Trains T2 Airport line and NSW TrainLink Southern Highlands Line services.  It is the southern extremity of the electrified Sydney Trains network.

Mascot railway station: Mascot railway station is located on the Airport line, serving the Sydney suburb of Mascot.  It is served by Sydney Trains T2 Airport line services.

Elizabeth Bay House: Elizabeth Bay House is an historic Colonial style home in the suburb of Elizabeth Bay in Sydney, New South Wales, Australia.  Built between 1835 and 1839, Elizabeth Bay House was known as 'the finest house in the colony'.  Elizabeth Bay House is a home in the Regency style, originally surrounded by a 54 acre garden, but now situated within a densely populated inner city suburb.  It is managed by the Sydney Living Museums as a museum that is open to the public, on behalf of the Office of Environment and Heritage, an agency of the Government of New South Wales.

Domestic Airport railway station, Sydney: Domestic Airport railway station is located on the Airport line, serving Terminals 2 and 3 at Sydney Airport.  It is served by Sydney Trains T2 Airport line services.

Green Square, New South Wales: Green Square is a district in the inner-east of Sydney, in the suburbs of Alexandria, Zetland, Waterloo and Beaconsfield.  It is 4 km south of the Sydney central business district and is part of the local government area of the City of Sydney.

Alexandria, New South Wales: Alexandria is a suburb in the inner-east of Sydney, New South Wales, Australia.  Alexandria is located 4 kilometres south of the Sydney central business district and is part of the local government area of the City of Sydney.  The postcode is 2015.

Supporting paragraphs: Green Square railway station Alexandria, New South Wales
Answer: Sydney