A comparison using like or as is a simile.
Answer:
Contemplation
Explanation:
'Contemplation' is the stage of change in which people are willing to change themselves and begin to propagate a healthy behavior in the upcoming six months. <u><em>At this stage, they are well aware of the pros associated with this changed behavior but a little less aware of the consequences</em></u>. Sarah would be called to be in this stage as she has decided to adopt a healthy behavior('started reading books on weight loss and concerned about her diet and physical activity'). This reflects that she is aware of the pros of this change but a little about the consequences associated with it.
