Which of the following is not an address register?Select one:A.Source Index Register.B.Program Counter.C.Stack Pointer.D.Code Segment Register.

To determine which of the options is not an address register, we need to understand what an address register is.

An address register is a type of register that holds memory addresses. It is used to store the location of data or instructions in memory.

Let's analyze each option to see if it fits the definition of an address register:

A. Source Index Register: This is a type of register that is used for indexing operations. It holds the index value used for accessing elements in an array or table. It does not directly hold memory addresses, so it is not an address register.

B. Program Counter: This register is used to store the address of the next instruction to be executed. It holds memory addresses and is used for program control. Therefore, it is an address register.

C. Stack Pointer: This register is used to keep track of the top of the stack in memory. It holds memory addresses and is used for managing the stack. Therefore, it is an address register.

D. Code Segment Register: This register is used to store the starting address of the code segment in memory. It holds memory addresses and is used for accessing instructions. Therefore, it is an address register.

Based on our analysis, the option that is not an address register is A. Source Index Register.