Kelly has a gym membership but has stopped working out because her neighbor who used to drive them there has moved to another city. Kelly is experiencing what kind of barrier to behavior change?

logistical

Explanation:

Based on the scenario being described within the question it can be said that Kelly is experiencing a logistical barrier to behavioral change. This refers to something that is preventing you from being able to continue progressing forward and achieving the change that is desired. In this case the neighbor not driving Kelly anymore is the barrier because without this assistance Kelly can no longer get to the gym everyday and workout, which in term prevents her from achieving the change she has been working towards.