Question: Which of the following activities is an example of reinforcement on a variable ratio schedule? Group of answer choices A student checking email at random times throughout the day, waiting for an important message to come in. An employee receiving a raise after his yearly review. A social influencer waiting to receive likes after posting a picture on Instagram. A salesperson who receives a commission for every 5 items sold. A fly fisherman catching a fish after casting his bait line an unpredictable number of times.