The question asks to identify the primary memory of a computer from the given options.

Primary Memory Identification

Primary memory, also known as main memory or internal memory, is the memory that the computer's CPU can access directly and quickly. It holds data and instructions that are currently being used.

Analyzing Computer Memory Options

• RAM (Random Access Memory): This is a type of volatile primary memory. The CPU uses RAM to store data it needs to access quickly while running applications. It is volatile, meaning its contents are lost when the power is turned off.
• DVD (Digital Versatile Disc): This is an optical disc storage medium used for storing data. It is a form of secondary memory (or external storage), not primary memory, because it's slower and not directly accessed by the CPU for active processing.
• USB (Universal Serial Bus) Drive: This is a portable flash memory storage device. Like DVDs, USB drives are considered secondary memory, used for long-term storage and transferring files, not for active processing by the CPU.
• CD (Compact Disc): Similar to DVDs, CDs are optical discs used for data storage. They are classified as secondary memory or external storage.

Conclusion on Primary Memory

Based on the definitions, RAM is the only option listed that functions as the computer's primary memory. The CPU directly interacts with RAM for active tasks, making it essential for the computer's immediate operation.

Therefore, RAM is the primary memory of a computer.