Which of the following is the last part of ICMP message

Solution

Why this is correct:
ICMP messages typically follow: Type (8 bits), Code (8 bits), Checksum (16 bits), followed by a variable part (rest of header specifics) and then the data/payload region (variable length). The payload/data is the final variable-length portion. Why the others are wrong: 1.      "Extended Header" is not the standard last field name. 2.      Checksum appears earlier (after Type and Code), not last. 3.      Code is an early fixed field, not the last field.