Answer:
Emotional contagion
Step-by-step explanation:
In psychology, the term emotional contagion refers to the phenomenon by which one person's emotions trigger similar emotions in other people. In other words, individuals tend to express and feel emotions that are similar to the ones from the people they are interacting with.
In this example, Danielle is happy at first but then, while talking on the phone with her friend, the sadness in her friend's voice causes Danielle's mood to change from happy to sad. We can see that Danielle friend's sadness triggered feelings of sadness in Danielle too. Therefore, this change in mood resulting from the tone of her friend's voice is called Emotional contagion.