Answer:
d.a fixed-ratio schedule. Â Â Â Â Â Â Â Â
Explanation:
Fixed-ratio schedule: In psychology, the term fixed-ratio schedule is being used in operant conditioning and is defined as a reinforcement schedule in which a particular response is being reinforced after a specific number of responses.
Example: A cat will be given food only after a fixed number of a particular response or behavior i.e if the cat will 'meow' three times then the cat will be given food.
In the question above, the statement signifies a fixed-ratio schedule of reinforcement.