Answer:
She is demonstrating infantile amnesia.
Step-by-step explanation:
Infantile amnesia may be defined as the condition in which the child is unable to memorize or retrieve the episodic memories. This occurs before the age of the two to four years.
The Brianna is unable to recognize the girl with whom she had met when she was 2 years old. She has shown the condition of the infantile amnesia as Brianna was unable to memorize the condition that had occurred at tha age of 2.
Thus, the answer is infantile amnesia.