Answer - C.
The main reason for such errors is that throttling occurs when many requests are sent via API calls.
The best way to mitigate this is to stagger the rate at which you make the API calls.
This is also given in the AWS Documentation.
In addition to simple retries, each AWS SDK implements an exponential backoff algorithm for better flow control.
The idea behind exponential backoff is to use progressively longer waits between retries for consecutive error responses.
You should implement a maximum delay interval, as well as a maximum number of retries.
The maximum delay interval and maximum number of retries are not necessarily fixed values and should be set based on the operation being performed and other local factors, such as network latency.
Option A is invalid because this accounts for the same thing.
It's basically the number of requests that is the issue.
Option B is invalid because any way you have to add the timestamps when sending the requests.
Option D is invalid because this would not help in the issue.