which of the following features in a cost effective and efficient manner?

Refer to the architecture diagram above of a batch processing solution using Simple Queue Service (SOS) to set
up a message queue between EC2 instances which are used as batch processors Cloud Watch monitors the
number of Job requests (queued messages) and an Auto Scaling group adds or deletes batch servers
automatically based on parameters set in Cloud Watch alarms. You can use this architecture to implement
which of the following features in a cost effective and efficient manner?

A.
Reduce the overall lime for executing jobs through parallel processing by allowing a busy EC2 instance that
receives a message to pass it to the next instance in a daisy-chain setup.

B.
Implement fault tolerance against EC2 instance failure since messages would remain in SQS and worn can
continue with recovery of EC2 instances implement fault tolerance against SQS failure by backing up messages
to S3.

C.
Implement message passing between EC2 instances within a batch by exchanging messages through SOS.

D.
Coordinate number of EC2 instances with number of job requests automatically thus Improving cost
effectiveness.

E.
Handle high priority jobs before lower priority jobs by assigning a priority metadata field to SQS messages.