Explanation:

In computer architecture, an instruction is a command given to the processor to perform a specific operation. Instructions are encoded in binary format and are stored in memory. The size of an instruction determines the amount of memory required to store it.

One-Byte Instruction:

A one-byte instruction is an instruction that requires only one byte of memory to store it. This means that the opcode, which represents the operation to be performed, is encoded in a single byte.

Opcode:

The opcode is a portion of the instruction that specifies the operation to be performed. It is usually the first part of the instruction and is used by the processor to determine the action it needs to take.

Explanation of Options:

a) 2 bytes: This option suggests that a one-byte instruction requires 2 bytes of memory to store it. However, this is incorrect because a one-byte instruction should only require 1 byte of memory.

b) 1 byte: This option is correct. A one-byte instruction requires 1 byte of memory to store it. The opcode is encoded within this single byte, allowing the processor to interpret and execute the corresponding operation.

c) 3 bytes: This option suggests that a one-byte instruction requires 3 bytes of memory to store it. However, this is incorrect because a one-byte instruction should only require 1 byte of memory.

d) 4 bytes: This option suggests that a one-byte instruction requires 4 bytes of memory to store it. However, this is incorrect because a one-byte instruction should only require 1 byte of memory.

Summary:

The correct answer is option 'B' - One-byte instructions require only 1 byte of memory to store them. The opcode, which represents the operation to be performed, is encoded within this single byte.