hich of following is a characteristic of electronic code book $($ECB$)$ mode?

Only one character is processed at a time.

It requires access to a synchronous counter for both the sender and receiver of the message.

Each block of plaintext is XORed with the previous block of ciphertext before being encrypted, making it susceptible to attacks.

Two identical plaintext blocks are encrypted into two identical ciphertext blocks, making them susceptible to attacks.