<em>Marshall notices that his dog is not obeying his commands effectively or steadily that leads him to the conclusion to describe this behavior as inconsistent. </em>This description of his problem, that it reacts to his commands sometimes and not the other times which would help the trainer to deal with it accordingly. 'Inconsistent' word here is the most compatible with the dog's situation where it is unsteady in its behavior and responding to Marshall sometimes and sometimes not. It is like an 'on and off' situation for him.