Which of the following device names is reserved for the root device for Linux instances of Amazon EC2?

A.
/dev/sda1

B.
/dev/sd[b-e]

C.
xvd[a-e]

D.
/dev/sd[f-p][1-6]

Explanation:
/dev/sda1 is the name of the device reserved for the root device for Linux instances.
http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/device_naming.html