Answer:
![\boxed {\tt Kinetic \ energy}](https://img.qammunity.org/2021/formulas/chemistry/high-school/xanpyjyvem7pnjf1xzpkbqnr48efiktgrs.png)
Step-by-step explanation:
First, let's define kinetic energy and potential energy.
Kinetic
- energy an object has due to motion
Potential
- energy an object has stored due to its position, charge, arrangement or other factors
Since the boy is walking down the street, the boy is in motion. Therefore, the energy must be kinetic energy.