Which of the following is a variable-length, letter-and-number error-detection method where, on the sender side, the data is appended with the…

Which of the following is a variable-length, letter-and-number error-detection method where, on the sender side, the data is appended with the remainder obtained by dividing the data bit sequence by a specific generator polynomial, and on the receiver side, error detection is performed by checking whether the received sequence is divisible by the same polynomial?

1. a) CRC
2. c) Horizontal parity check
3. b) Hamming code
4. d) Vertical parity check