Question

demand for soft drinks outside an airport is more elastic than inside of the airport because:
necessities have less elastic demand.
fewer choices mean more inelastic demand.
specific brands tend to have more elastic demand than categories of goods.
more choices make demand more elastic.

Explanation:

The number of available substitutes affects demand elasticity. Outside an airport, there are more options for soft - drinks (more sellers, more brands etc.), so consumers can easily switch if prices change. Inside an airport, there are fewer choices, so consumers are less responsive to price changes (inelastic demand). More choices make demand more elastic.

Answer:

more choices make demand more elastic.