A company is building a voting system for a popular TV show. Viewers watch the performances then visit the show’s website to vote for their favorite performer. It is expected that the site will receive millions of visitors in a short period of time after the show is finished. The visitors will first login to the site using their Amazon.com credentials and then submit their votes. After the voting is completed, the page will display the vote totals. The company needs to build a site to handle the rapid influx of traffic while maintaining good performance.

Answer options:

A.Use CloudFront and an Elastic Load balancer in front of an auto-scaled set of web servers. The web servers will first login with the Amazon service to authenticate the users, then process the users` votes and store the votes into a multi-AZ Relational Database Service instance.
B.Use CloudFront and the static website hosting feature of S3 with the Javascript SDK to call the login with Amazon service to authenticate the user. Configure IAM users to gain permissions to a DynamoDB table to store the users` votes.
C.Use CloudFront and an Elastic Load Balancer in front of an auto-scaled set of web servers. The web servers will first login with Amazon service to authenticate the user. The web servers will process the users` votes and store the votes into a DynamoDB table that has a large read capacity unit.
D.Use CloudFront and an Elastic Load Balancer in front of an auto-scaled set of web servers. The web servers will first login with Amazon service to authenticate the user. The web servers will process the users` votes and store the votes into an SQS queue using IAM Roles for EC2 Instances to gain permissions to the SQS queue. A set of application servers will then retrieve the items from the queue and update the `vote totals` into a DynamoDB table.

Answer - D
This scenario has the following architectural considerations: (1) the application needs to be scalable to handle traffic coming from millions of users, (2) the application should handle the rapid influx of traffic, maintaining good performance. 
When the application needs to handle the data coming from millions of users, always think about using DynamoDB. Also, to provide the global users with high-performance content access, you need to consider CloudFront. You need to set the appropriate IAM Role for the front end/web servers to access DynamoDB tables.
Option A is incorrect because multi-AZ RDS is not a preferable solution compared to DynamoDB.Option B is incorrect because IAM roles should be used to provide permissions to write the DynamoDB table.
Option C is incorrect because DynamoDB needs a high write capacity unit. With this option, DynamoDB may have a performance issue.
Option D is CORRECT because (a) it is highly scalable, (b) creates appropriate IAM Role to access the DynamoDB database, and (c) more importantly uses SQS to hold the user data/votes such that the application does not consume read and write provisioned capacity of DynamoDB. 
As per the scenario, once the user completes the voting, the web page should display the total number of votes submitted online.
Option D also includes an Autoscaling group of EC2 instances to handle the traffic.
Hence option D is optimal.