Right answer: turísticas
If you travel to another country for tourism you are a visitor or tourist. Generally tourists like to visit as many touristic places as possible.
So, the right option is C, turísticas (tourist) and the complete sentence is:
Cuando viajo, me gusta visitar todas las atracciones turísticas.
When I travel, I like to visit all the tourist attractions.
The options agitadas (hetic areas), cortas (short) and libres (free areas) are not correct because are not in the context of what a tourist generally does.
