Answer:
She should feed him only when her bell rings and never feed him after the telephone or the bell.
Explanation:
Yolanda must make the dog understand that he will only receive food when her bell rings. For this, she must deliver food to the dog, only when her bell rings and never with the ringing of other objects such as the telephone or the bell. In this way, the dog will associate the receipt of food with Yolanda's bell and will not respond to any other sounds that are not associated with food.
