In psychology, the word conditioning refers to a type of learning in which a stimulus such as a situation, noise, image, etc. leads to a response that can be an action or physiological response such as rapid heart beating. Additionally, in conditioning one stimulus can be associated with another element and therefore the first stimulus is replaced by the second. This is the case of Gina, in which the attack of a dog which led to a natural response that was rapid heart beating is replaced by the noise of bark of any dog and that makes Gina react in the same way that in the real attack when she hears a dork barking. Thus, this is an example of conditioning.
The answer to your question is A. "Others weren't so lucky. In the rush and panic, a number of people either lost their footing or were accidentally pushed from the sidewalk and into the busy street."
