A high-speed memory is placed between the Central Processing Unit (CPU) and the primary memory known as ______ memory.

Correct option is C

Cache memory is a high-speed memory placed between the CPU and the primary memory (RAM) to store frequently accessed data and instructions. This reduces the time the CPU takes to access data from the main memory.
(a) Read-only: This is incorrect because read-only memory (ROM) is non-volatile and used to store firmware, not for high-speed operations between CPU and RAM.
(b) Virtual: This is incorrect because virtual memory refers to the space on a hard drive that is used to simulate additional RAM, not high-speed memory like cache.
(d) Secondary: This is incorrect because secondary memory refers to storage devices like hard drives, which are much slower than cache memory.