9. Alice wishes to regularly send Bob a plaintext message P or P2. On each occa- sion she chooses to send either P or P2, but on average she chooses the plaintext P, twice as often as she chooses the plaintext P2. Each time, Alice uses a (very simple) symmetric cryptosystem, with the same fixed key K, to encrypt the plaintext. When she chooses Pt, the ciphertext is C,- Ek(P): when she chooses Ps, the ciphertext is G-ExlP2). Suppose an attacker knows the only possible plaintext messages are P and P2 (a) Suppose the attacker does not know Alice chooses P, twice as often as Pa What observation will the attacker, who can only see the ciphertexts sent from Alice to Bob, make