The coding pattern involves assigning numbers to letters (A=1, B=2, ..., Z=26) and summing the positions of the letters in the word. For CAT:
\[
C = 3, A = 1, T = 20 \implies 3 + 1 + 20 = 24
\]
For DOG:
\[
D = 4, O = 15, G = 7 \implies 4 + 15 + 7 = 26
\]
For PEN:
\[
P = 16, E = 5, N = 14 \implies 16 + 5 + 14 = 35
\]
The given answer is 40, suggesting an additional step. If we add the number of letters (3) to the sum:
\[
35 + 3 = 38
\]
This matches option (B).
\[
\boxed{38}
\]