Users Report Intermittent Availability of a Web Application Hosted on AWS

Users report intermittent availability of a web application hosted on AWS. Monitoring systems report an excess of abnormal network traffic followed by high CPU utilization on the application web tier. Which of the following techniques will improve the availability of the application? (Choose two.)

A) Deploy AWS WAF to block all unsecured web applications from accessing the internet.
B) Deploy an Intrusion Detection/Prevention Systems (IDS/IPS) to monitor or block unusual incoming network traffic.
C) Configure security groups to allow outgoing network traffic only from hosts that are protected with up-to-date antivirus software.
D) Create Amazon CloudFront distribution and configure AWS WAF rules to protect the web applications from malicious traffic.
E) Use the default Amazon VPC for external-facing systems to allow AWS to actively block malicious network traffic affecting Amazon EC2 instances.