$12)$ Longitudinal Redundancy Check $($LRC$)$ is used to protect the

following data:

$10101001$

$00111001$

$1101110111100111$

The VRC bits will be given by:

$($a$)$

$01010101($b$)10101010($c$)10111011($d$)10111010$

$12\mathrm{.}1($a$)$

$($b$)$

$($c$)$

$($d$)$

The efficiency of this code is:

$($a$)10\%$

$($b$)80\%($c$)90\%($d$)100\%$