No. RAM is generally electronic, not optical. ROM is often optical, though. CDs and DVDs are good examples of optical media.
a compact disc
No. Optical storage uses lasers to "see" the media (e.g. CD, DVD, HD-DVD and BluRay)
Optical media include CD-ROMs, DVD ROMs, and Blu-Ray disks.
An SD Card or a Removable Disk
One storage device is RAM. Also Magnetic Media, Flash Media, and Optical media. Your welcome :)
CD and DVD disks are used by optical disc drives.
A DVD is the media that data is written to. A DVD-ROM, DVD-RAM, DVD/RW etc is the optical storage device.