Instruction Cache – Used for storing instructions that are frequently used.
Instruction Register – Part of CPU’s control unit that stores the instruction currently being executed.
Instruction Opcode – It is the portion of a machine language instruction that specifies the operation to be performed.
Translation Lookaside Buffer – It is a memory cache that stores recent translations of virtual memory to physical addresses for faster access.
So, all the above except Instruction Opcode are memories.
Thus, C is the correct choice.
Ref: www.geeksforgeeks.org/gate-gate-cs-2002-question-13/