Answer: The role of the learner here, the dog, is passive. But, it has a voluntary response - an emotionally motivated action - to stimulations like Maricella leaving to work or taking the car keys, what denotes that the response is post stimulation, naturally.
Therefore, letter "c" is the option that best satisfies the proposed question, once the phenomenon could be majorly described as classical conditioning, but, has an inclusion of the voluntary response factor that is generally imputed to the operant conditioning, hence not being possible to describe the situation through only one learning process.