Regarding constructing a good encryption algorithm， what does creating an avalanche effect indicate？（）

• A、Altering the key length causes the ciphertext to be completely different
• B、Changing only a few bits of a ciphertext message causes the plain text to be completely different
• C、Altering the key length causes the plain text to be completely different
• D、Changing only a few bits of a plain-text message causes the ciphertext to be completely different