According to Hatfield and Berscheid, physiological arousal and the belief that someone is the cause of this arousal is the source of?

Passionate attraction

Explanation:

Passionate attraction: In psychology, the term passionate attraction was proposed by Elaine Hatfield and is defined as a particular state in an individual's life that creates an intense longing to get along with the other person.

The passionate attraction is considered to be a part of a relationship and two-person involve in it feel intense emotions and feelings for each other. It often leads to creating physical arousal and the other person is the cause of arousal for two different people.

In the question above, the statement signifies the passionate attraction.