Final answer:
The conditioned response in this scenario is Sandy smiling.
Step-by-step explanation:
The conditioned response in this scenario is Sandy smiling. Initially, when Ronald met Sandy, she did not smile, indicating that she did not like him. However, as Ronald started buying Sandy flowers, which she really likes, Sandy began to associate the presence of flowers with happiness and started smiling when she thought of Ronald. Therefore, Sandy's smiling is the conditioned response in this situation.