Answer:
A) fixed-ratio
Explanation:
The fixed ratio is the ratio that represents the reinforcement schedule. Here the delivery of the reinforcement could be done when the number of responses is completed and finished
Since in the given situation, it is mentioned that a toddler has learned about the jack and it wont be operate till she turns the hand crank approx and exact 10 mins
So this situation represents the fixed ratio
hence, the correct option is A