Answer:
b. infatuated love
Step-by-step explanation:
The triangular theory of love was developed by Robert Sternberg, who propounded that love can be defined or given meaning based on three major components of love, which are intimacy, commitment, and passion.
According to Sternberg's triangular theory of love, a type of love that is characterized by mere passion or lust for someone without a deep sense of intimacy and no strong commitment, can be regarded as infatuation love.
From the scenario sited in the question, Brian is feeling infatuation love, according to the triangular theory of love.