Which scaling policy in an Auto Scaling Group adjusts capacity based on a target metric value?

Target Tracking Scaling is the correct choice because it allows an Auto Scaling group to automatically adjust its capacity based on a specified target metric value. For instance, you could set a target of maintaining an average CPU utilization of 50%. The Auto Scaling service will then automatically increase or decrease the number of instances in the group to keep the average CPU utilization close to that target.

This scaling policy simplifies management by using a single metric and target to drive scaling actions, making it easier for users to specify desired performance levels without needing to define specific thresholds for scaling actions. It dynamically adjusts capacity in response to changes in load, which optimally balances cost and performance.

Other options do not match this functionality. Step Scaling requires users to define specific scaling actions based on defined metrics and thresholds, making it more complex to manage compared to target tracking. Simple Scaling is a more basic form of scaling that responds to changes in load but does not specifically aim at maintaining a target metric. Dynamic Scaling is a broader term that can refer to any adjustments made to capacity based on varying conditions, but in the context of this question, it doesn't specifically define the automatic adjustment based on a target metric, which is the hallmark of target tracking.