Answer:
Neutral Stimulus
Explanation:
Neutral stimulus is a type of stimulus that doesn't produce or elicit any response, but catches or attracts attention. But when a neutral stimulus is combined with an unconditioned stimulus repeatedly, the neutral stimulus then result to a conditioned stimulus which also further produces a response referred to as conditioned response. Hence, when the neutral stimulus produces a conditioned response, it then becomes a conditioned stimulus
From the example, the light is considered to be a neutral stimulus because it is the first time and it just caught the attention of the dog.