You have an Autoscaling Group configured to launch EC2 Instances for your application. But you notice that the Autoscaling Group is not launching instances in the right proportion. In fact, instances are being launched too fast. What can you do to mitigate this issue? Choose 2 answers from the options given below.

Answer options:

A.Adjust the cooldown period set for the Autoscaling Group.
B.Set a custom metric which monitors a key application functionality for the scale-out process.
C.Adjust the CPU threshold set for the Autoscaling scale-in and scale-out process.
D.Adjust the Memory threshold set for the Autoscaling scale-in and scale-out process.

Answer – A and B
The Auto Scaling cooldown period is a configurable setting for your Auto Scaling group that helps ensure that Auto Scaling doesn`t launch or terminate additional instances before the previous scaling activity takes effect. 
For more information on the cool down period, please refer to the below link:
http://docs.aws.amazon.com/autoscaling/latest/userguide/Cooldown.html
Also, it is better to monitor the application based on a key feature and then trigger the scale-in and scale-out feature accordingly. In the question, there is no mention of CPU or memory causing the issue.