Justin is teaching his dog, Tiara, to jump on command. He gives her a treat when she jumps on command only when the treats are with him. When the treats are not in his reach, he does not give her a treat. In this context, Justin is using

Partial Reinforcement

Explanation:

In partial reinforcement, the response is reinforced only part of the time. Its disadvantage is that the learned behaviors are acquired more slowly but its advantage is that the response is more resistant to extinction. The student or object will almost not forget what they they were taught.

This means that a partial reinforcement schedule the response is reinforced only part of the time. Partial reinforcement is also known as intermittent reinforcement.

This is what Justin is using on the Dog. He gives it treats only when he have, it might prolong the dog's learning process but the dog won't forget what it learnt in a hurry.