Correct answers - "A snapshot of an encrypted volume is always encrypted & Restoring a volume
from an encrypted snapshot must be an encrypted volume" : Amazon EBS encryption uses AWS Key
Management Service (AWS KMS) customer master keys (CMKs) when creating encrypted volumes and any
snapshots created from them.
"A snapshot of an encrypted volume can be encrypted or unencrypted" - There is no direct way to
encrypt an existing unencrypted volume, or to remove encryption from an encrypted volume
"Restoring a volume from an encrypted snapshot can be an un-encrypted volume" - Volumes restored
from encrypted copy are also encrypted
"EBS encryption impacts performance" - You can expect the same IOPS performance on encrypted
volumes as on unencrypted volumes