What is the problem and a valid solution?

You have launched an EC2 instance with four (4) 500GB EBS Provisioned lOPS volumes attached The EC2 Instance Is EBS-Optimized and supports 500 Mbps throughput between EC2 and EBS The two EBS volumes are configured as a single RAID o device, and each Provisioned lOPS volume is provisioned with 4.000 lOPS (4 000 16KB reads or writes) for a total of 16.000 random lOPS on the instance The EC2 Instance initially delivers the expected 16 000 lOPS random read and write performance Sometime later in order to increase the total random 1/0 performance of the instance, you add an additional two 500 GB EBS Provisioned lOPS volumes to the RAID Each volume Is provisioned to 4.000 lOPs like the original four for a total of 24.000 lOPS on the EC2 instance Monitoring shows that the EC2 instance CPU utilization increased from 50% to 70%. but the total random lOPS measured at the instance level does not increase at all.

What is the problem and a valid solution?
A . Larger storage volumes support higher Provisioned lOPS rates: increase the provisioned volume storage of each of the 6 EBS volumes to lTB
B . The EBS-Optimized throughput limits the total lOPS that can be utilized use an EBS-Optimized instance that provides larger throughput.
C . Small block sizes cause performance degradation, limiting the 1’0 throughput, configure the instance device driver and file system to use 64KB blocks to increase throughput.
D . RAID 0 only scales linearly to about 4 devices, use RAID 0 with 4 EBS Provisioned lOPS volumes but increase each Provisioned lOPS EBS volume to 6.000 lOP
F . The standard EBS instance root volume limits the total lOPS rate, change the instant root volume to also be a 500GB 4.000 Provisioned lOPS volume.

Answer: E