I believe the answer is: the hospital
Conditioned stimulus refers to a stimulus that already become a trigger to a certain response due to the process of classical conditioning. From the example above, alexis start to cry after she saw a hospital. Because of this, we can say that the sight of hospital act as the trigger the elicit the response.
C. The Three Gorges Dam
was built to control the devastating effects of flooding in China.
The opera as a form of entertainment was largely limited to people with high incomes.
Opera originated in Italy at the end of the 16th century and it is a form of theatre in which music has a leading role and the parts are taken by singers. The audience wer weatlhy people from the high society.
a European intellectual movement of the late 17th and 18th centuries emphasizing reason and individualism rather than tradition. It was heavily influenced by 17th-century philosophers such as Descartes, Locke, and Newton, and its prominent exponents include Kant, Goethe, Voltaire, Rousseau, and Adam Smith.