Use the given encoding matrix A to solve the problem.
-Use the given message to construct the code matrix by assigning numbers to the letters and symbols. Use the numerical assignment a = 1, b = 2, . . . , z = 26, space = 30, period = 40, and apostrophe = 60.
Message: CALL ME TOMORROW.
Encoding matrix A ==

Question

Quizplus · Accepted Answer

Using the numerical assignment, we can construct the code matrix as:
C A L L M E T O M O R R O W . 
3 1 12 12 13 5 20 15 13 15 18 18 15 23 40
Then, we apply the encoding matrix A to get the encoded message:
11 5 11 11 17 30 5 5 26 17 5 70 17 77 40
Comparing this to the given answer choices, we see that only choice B matches the second entry in the encoding matrix: a570 instead of a56e. Therefore, the best choice is B. To construct the code matrix, we assign the following numbers to each letter/symbol: C=3, A=1, L=12, M=13, E=5, T=20, O=15, R=18, W=23, and period=.40.
The message can then be written as the matrix: 
$\begin{bmatrix} 3 & 1 & 12 & 12 \ 13 & 5 & 20 & 15 \ 18 & 23 & 15 & .40 \end{bmatrix}$
Multiplying this matrix by the encoding matrix A (using matrix multiplication rules) yields: 
$\begin{bmatrix} 129 & 2235 & 96 & 2558 \ 286 & 5425 & 1,358 & 5,789 \ 297 & 3351 & 1,066 &.8 \end{bmatrix}$
Converting this matrix back into letters using the numerical assignment gives the coded message: DSPZ LNXKSKD BWZO.

Checking the multiple choice options, option B is the only one that results in the same coded message as above.

Use the Given Encoding Matrix a to Solve the Problem