Which storage medium is a characteristic feature of Sun Solaris systems?

SPARC is the correct choice because it refers to a specific architecture designed by Sun Microsystems, which is directly associated with Sun Solaris systems. SPARC stands for Scalable Processor Architecture and has been integral in defining the design and capabilities of Sun's hardware platforms. Solaris is optimized for running on SPARC processors, leveraging their architecture to deliver enhanced performance and reliability, particularly in enterprise environments.

In contrast, the other options represent various types of storage or interfaces rather than characteristics of Solaris systems themselves. HDD (hard disk drives) and SCSI (Small Computer System Interface) are primarily types of storage media and data transfer protocols, respectively, which can be used across numerous systems beyond those made by Sun Microsystems. A DVD is another type of storage medium but is not specifically linked to the Solaris operating system or its platforms. Therefore, SPARC stands out as a defining feature that closely relates to the Solaris operating system's hardware compatibility and performance optimization.