Correct : b

Analysing each addressing mode:
P. Immediate → 4. Constant
In immediate addressing, the operand is directly embedded in the instruction itself. This is used to represent a constant value. Example: MOV R1, #5 (5 is a constant).
Q. Indirect → 2. Pointer
In indirect addressing, the address field contains a pointer — the address of a memory location that holds the actual address of the operand. This is exactly how pointers work.
R. Base with index → 1. Element of an array
Base register holds the starting address of an array and the index register holds the offset for each element. This is the classic way to access array elements. Example: Base + Index = address of arr[i].
S. Base with offset → 3. Element of a record
Base register holds the starting address of a record (struct) and a fixed offset is used to access a specific field within it. This is how struct members are accessed in memory.
The correct match is P-4, Q-2, R-1, S-3 (Option B)