Which of the following components are involved in a single round of S$-$DES encryption? Select one: a$.$ Plaintext formatting, error correction codes, data compression, and network security protocols. b$.$ Message digest calculation, encryption mode selection, padding techniques, and digital signature. c$.$ Key generation, key schedule, rounds of Feistel cipher, and final permutation. d$.$ Data expansion, S$-$boxes, permutation, and XOR operations.