Apigeon's behaviour of pecking a blue light was reinforced after every fifth attempt. this is an example of what?

Fixed ratio schedule Reinforcement

Explanation:

Fixed-ratio schedule reinforcement is a principle of reinforcement in ope-rant conditioning. It is associated with ope-rant conditioning. What is meant to fix? fixed means to reinforcement at  a consistent schedule. In this process how often provided reinforcement. It is a reward earning by doing something positive. It motivates the stimulus to repeat that same behavior. So a fixed ratio schedule means that reinforcement whenever specific behaviors take place, or we can say that it is presented every fifth time, thirteenth time or nth time. The schedule is constant at every nth time. If reinforcement is given randomly then it could not be consistent or fixed. Reinforcement occurs at a set of numbers.

the answer is d.index