Adding Aer Lingus to its portfolio of airlines - British Airways, Iberia and Spanish budget carrier Vueling - opens a new avenue of growth for IAG, allowing it to expand capacity on lucrative transatlantic routes by using Dublin Airport.
Take context from the input text and decide on the accurate relationship between 'Aer Lingus' and 'Dublin' from the options provided.
Options: platform, original broadcaster, location of formation, parent organization