<s>[INST] The next text is a question of a member of the European parliament:"Esbjerg airport and Billund airport are competitors for departures to London. Esbjerg airport is owned by the local authority, while Billund airport is privately owned.  When an airline makes use of an airport, it has to pay an airport tax per passenger. It is the National Air Transport Authority which sets the rules for the level of these airport taxes. Billund airport states that, for the types of aircraft that Ryanair uses from Esbjerg to London, the tax will be DKK154 per departing passenger. It also states that, after an agreement with Esbjerg airport, Ryanair pays only DKK38 per departing passenger, and that the balance of DKK154 is paid by Esbjerg airport.  Will the Commission initiate an investigation into whether the agreement between Esbjerg airport and Ryanair for the payment of DKK38 per passenger, instead of the DKK154 set by the National Air Transport Authority, conflicts with the ban on state aid under EU law?"
Analyze carefully the text and assign it to the most relevant policy area among those listed below. Do not explain your answer and return only a number.
Policy area numbers: 1 = Macroeconomics
2 = Civil Rights, Minority Issues and Civil Liberties
3 = Health
4 = Agriculture and Fisheries
5 = Labour, employment and pensions
6 = Education
7 = Environment
8 = Energy
9 = Immigration
10 = Transportation
12 = Law and Crime
13 = Social welfare
14 = Regional and Urban issues and Planning
15 = Banking, finance and domestic commerce issues
16 = Defence
17 = Space, science, technology, and communications issues
18 = Foreign trade
19 = International affairs and foreign aid
20 = Governance and government
21 = Public Lands, Water Management and Territorial Issues
23 = Culture and media
[/INST]. Answer = [15]. </s>
Esbjerg airport and Billund airport are competitors for departures to London. Esbjerg airport is owned by the local authority, while Billund airport is privately owned.  When an airline makes use of an airport, it has to pay an airport tax per passenger. It is the National Air Transport Authority which sets the rules for the level of these airport taxes. Billund airport states that, for the types of aircraft that Ryanair uses from Esbjerg to London, the tax will be DKK154 per departing passenger. It also states that, after an agreement with Esbjerg airport, Ryanair pays only DKK38 per departing passenger, and that the balance of DKK154 is paid by Esbjerg airport.  Will the Commission initiate an investigation into whether the agreement between Esbjerg airport and Ryanair for the payment of DKK38 per passenger, instead of the DKK154 set by the National Air Transport Authority, conflicts with the ban on state aid under EU law?