You are programming a buffer overflow exploit and you want to create a NOP sled of 200 bytes in the program exploit.c What is the hexadecimal value of NOP instruction?

0x60 is the opcode for the PUSHA instruction on x86, which pushes all general-purpose registers onto the stack, not a no-operation instruction.

0x80 is not a standalone NOP opcode; it is the leading byte of multi-byte arithmetic and logic group instructions such as ADD and SUB with immediate operands.

0x70 is the opcode for JO (Jump if Overflow), a conditional branch instruction, not a no-operation instruction.

0x90 is the single-byte opcode for the NOP instruction on x86 processors, which causes the CPU to do nothing and advance to the next instruction. In buffer overflow exploitation, a NOP sled is a sequence of consecutive 0x90 bytes placed before shellcode so that any jump landing within the sled slides execution forward into the payload. This increases the reliability of exploits when the exact return address cannot be pinpointed.