Final answer:
Observational learning is the most appropriate explanation for humans and pigeons engaging in spontaneous imitation.
Step-by-step explanation:
In the case of humans and pigeons engaging in spontaneous imitation, the most appropriate explanation would be D) It is a result of observational learning.
In observational learning, individuals learn by observing others and imitating their behavior. This type of learning involves the use of mirror neurons, which are specific neurons that fire both when an individual performs an action and when they see someone else performing the same action.
In the case of humans and pigeons imitating each other, it is likely that they are observing and learning from each other's behavior, leading to the appearance of similar behavior.