An Auto Scaling group for a web application experiences slow scale-out because instance bootstrapping scripts take a long time. The administrator wants to shorten time to serve traffic during scale-out without increasing excess capacity. Which change will accomplish this most effectively?

A warm pool allows you to maintain a set of pre-initialized instances that are ready to serve traffic immediately when a scale-out event occurs. This significantly reduces the time to serve traffic because the lengthy bootstrapping process is completed before the instances are attached to the Auto Scaling group. Modifying the launch configuration to use larger instance types might increase capacity per instance but doesn't address the slow bootstrapping time and could increase costs. Raising the Auto Scaling group’s minimum instance count increases excess capacity, which the question explicitly states to avoid. Adding a predictive scaling policy helps launch instances ahead of demand, but the instances still need to complete their bootstrapping process, which is the core problem identified.