Which of the below disk types is not backed by Solid State Drives (SSD)?

Answer options:

A.Standard persistent disks (pd-standard)
B.Balanced persistent disks (pd-balanced)
C.SSD persistent disks (pd-ssd)
D.Extreme persistent disks (pd-extreme)

Correct Answer: A
Option A is correct. Standard persistent disks (pd-standard) are backed by HDD (standard Hard Disk Drive). Hence, this option is Correct.
Option B is incorrect. Balanced persistent disks (pd-balanced) are backed by solid-state drives (SSD).
Option C is incorrect. SSD persistent disks (pd-ssd) are backed by solid-state drives (SSD).
Option D is incorrect. Extreme persistent disks (pd-extreme) are backed by solid-state drives (SSD).
https://cloud.google.com/compute/docs/disks#disk-types