I$\text{'}$m having issues with finding what the message is supposed to be$.$ I've found the decoded matrix but I don't understand how I$\text{'}$m supposed to find the letters. Please help with part b$.$

B be the encoding matrix,

where

B$=[[1,-3,1,-2],[2,-5,4,-2],[-3,9,-2,5],[4,-12,4,-7]]$

$($b$).$ Decode the row string below to reveal information about Test $2$:

message $=[-61,-49,180,-228,-88,-92,242,-325,-1,53,18,1,-40,-21$

$115,-146,-75,-42,218,-273,12,96,-15,54,-84,-57$

$243,-309,-58,-25,195,-226,-84,-57,243$

$-309,-6,65,20,-6,-90,-48,270,-333]$

$($c$).$ Can C be an encoding matrix? Justify your answer.

C$=[[6,2,0,1],[3,1,0,2],[0,3,2,0],[0,0,0,27]]$