Six-Year-Old Blair Liked Going to School Right Up Until Her

Six-year-old Blair liked going to school right up until her first-grade teacher, Ms. Hanemayer, took maternity leave. The substitute teacher, Mrs. Snarly, was strict and scolded Blair on several occasions, making her cry. On one Saturday morning as Blair was helping her father with grocery shopping, she suddenly came face to face with Mrs. Snarly. Blair instantly burst into tears. Blair's crying at just the sight of Mrs. Snarly is an example of:

A) instinctive drift.
B) an unconditioned response.
C) an unconditioned stimulus.
D) a conditioned response.