Stream ciphers and PRGS: We saw that one can build a secure stream cipher directly from a PRG. After learning about weaknesses found in RC4, Alice wants to encrypt a message for Bob using a stream cipher built from two candidate PRGs, call them G, and G. The goal is that if either is a secure PRG, the resulting cipher is a secure stream cipher. Assume that two keys ky, kz and two initialization vectors IV, IV, are chosen independently at random. Which of the following options will provide semantically secure encryption? If so, explain why. If not, explain a distinguishing attack. a. m G (kq, IV) V GZ (K2, IV2) (where V is a bitwise OR) (where is a bitwise exclusive-OR) b. m G,(k2, IV ) G2 (k, 1V2) C. [m G (k,, IV,)] || [m G (k2, 1V2)] (where || is a concatenation)