Use an arithmetic left$-$shift operation on the bit pattern $11011011.$ The pattern is an integer in $2$s complement format. $($Hint: find the normal representation first, then do the left$-$shift, and convert the result back to $2$s complement form.$)$

a$.$

$(10110110)2$

b$.$

$(11101110)2$

c$.$

$(10110101)2$

d$.$

$(10111000)2$