In parity, what are the two alternative systems if an error is detected?

A$.$ Block check character $($BCC$)$ and longitudinal redundancy check $($LRC$)$

B$.$ Automatic request for retransmission $($ARQ$)$ and symbol substitution

C$.$ Positive acknowledgement $($ACK$)$ and negative acknowledgement $($NAK$)$

D$.$ ARQ and end$-$of$-$message $($EOM$)$ indicator