In a certain letter code, the word DAY is represented by the sequence WZB. Using the same coding rule, how will the word MONDAY be written in that code language?

Introduction / Context:
This coding question uses a well known alphabet mirror or complement pattern often referred to as an Atbash type code. In such a system, letters are replaced by their mirror partners when the alphabet is written from A to Z and then from Z to A. By analyzing the mapping from DAY to WZB, we can discover how each letter is transformed and then apply the same rule to the longer word MONDAY.

Given Data / Assumptions:

• The word DAY is coded as WZB. • Target word to code: MONDAY. • There is a consistent one to one letter substitution. • Alphabet positions: A = 1, B = 2, …, Z = 26.

Concept / Approach:
The pattern can be recognized by observing that each coded letter seems to be the complement of the original letter with respect to the alphabet. In numeric terms, if a letter has position n, then its complement is the letter at position 27 − n. This maps the first letter A to the last letter Z, the second letter B to the second last letter Y, and so on. Once we confirm that this rule transforms every letter in DAY into WZB, we will apply it to each letter of MONDAY in turn.

Step-by-Step Solution:
Step 1: For D in DAY, position is 4. Its complement is at 27 − 4 = 23, which corresponds to W. This matches the code. Step 2: For A, position is 1. Complement is 27 − 1 = 26, which is Z. Again, this matches the code. Step 3: For Y, position is 25. Complement is 27 − 25 = 2, which is B. This matches the final coded letter. Step 4: This confirms that every letter is mapped to its mirror partner using the rule position to 27 minus position. Step 5: Now apply this rule to MONDAY. Write positions: M = 13, O = 15, N = 14, D = 4, A = 1, Y = 25. Step 6: Compute complements: for M, 27 − 13 = 14, which is N. Step 7: For O, 27 − 15 = 12, which is L. Step 8: For N, 27 − 14 = 13, which is M. Step 9: For D, 27 − 4 = 23, which is W. Step 10: For A, 27 − 1 = 26, which is Z. Step 11: For Y, 27 − 25 = 2, which is B. Step 12: Combining these gives NLMWZB as the code for MONDAY.

Verification / Alternative check:
A quick inspection of the options shows that only NLMWZB follows the same mirror mapping consistently from left to right. None of the other options aligns perfectly with the complement rule for all six letters. Therefore, the mapping is consistent and the answer is unique.

Why Other Options Are Wrong:
Option PLOWZB has incorrect first and second letters and does not follow the complement positions for M and O. Option NMLWZB swaps L and M in the middle, violating the correct complement for O and N. Option PQRWZB does not match the complement rule for any sequence of letters in MONDAY. Option NLOWZB alters the pattern in the third position and does not match the systematic mapping.

Common Pitfalls:
Students sometimes mistake this pattern for a simple forward or backward shift by a fixed number of positions. Another frequent error is to miscalculate alphabet positions, especially beyond the middle of the alphabet. Writing out A to Z with position numbers is a reliable way to avoid these errors in exam conditions.

Final Answer:
Using the mirror or complement coding rule, the word MONDAY is written as NLMWZB.