1. MAR <-- IR [ address]
---> The address field of the instruction is transferred to Memory Address Register ( MAR ) , this address field is then used to fetch the address of the operand.
2. MBR <--- Memory
--> After fetching the memory address, we transferred the contents/value of that address from memory to MBR .
3. IR [ address ] <-- MBR [ address]
---> The Instruction Register is updated from Memory Buffer Register . IR is now contain a direct memory address rather than indirect address .
So, these 3 micro operations perform Indirect cycle . Which is option D.
This is not a fetch cycle as in fetch PC is required , neither Interrupt nor execute cycle as there is no instructions like add,sub etc exists ..