Answer:
The correct answer is - modify her environment.
Step-by-step explanation:
Teresa has created the plan to achieve her goal of eating healthy food. Teresa knows that environment is one of major factors that help in achieving the plan of action as she asked her study group at library instead of fast food restaurant.
Modifying to place that is not related to food or unhealthy food is help in work on the plane of action to reach to goal.
Thus, the correct answer is - modify her environment.