In a certain code language, the English word "REGAINS" is written as "QDFZHMR". Using the same letter shifting pattern, how will the word "PRY" be written in that code language?

Introduction:
This coding and decoding question uses a simple alphabetic shift applied consistently to all letters. The word REGAINS is written as QDFZHMR. We must recognise the underlying shift and then apply it to the word PRY. This type of question checks your ability to handle basic Caesar cipher style transformations.

Given Data / Assumptions:
The provided mapping is REGAINS → QDFZHMR. We assume:
1) Each letter in the original word is replaced with exactly one letter in the coded word.
2) The same shift is applied to every letter of any word.
3) The alphabet is cyclic, so shifting backward from A leads to Z if needed.

Concept / Approach:
To uncover the rule, we compare each letter of REGAINS with the corresponding letter in QDFZHMR and compute the difference in terms of alphabet positions. If the difference is constant and negative, we have a fixed backward shift. Once the shift amount is confirmed, we apply it to the letters P, R, and Y in PRY.

Step-by-Step Solution:
Step 1: Determine the positions of letters in REGAINS: R=18, E=5, G=7, A=1, I=9, N=14, S=19.Step 2: Determine the positions of letters in QDFZHMR: Q=17, D=4, F=6, Z=26, H=8, M=13, R=18.Step 3: Compare each pair: R to Q is 18 to 17 (minus 1), E to D is 5 to 4 (minus 1), G to F is 7 to 6 (minus 1), A to Z is 1 to 26, which is effectively minus 1 with wrap around, and the same minus 1 shift holds for the remaining letters.Step 4: The rule is therefore: coded letter = original letter shifted backward by 1 position.Step 5: Apply this rule to PRY. P is 16 and becomes O (15), R is 18 and becomes Q (17), Y is 25 and becomes X (24).Step 6: So PRY is written as OQX in the code language.

Verification / Alternative check:
If we shift each letter of OQX forward by one position, we should recover PRY. O becomes P, Q becomes R, and X becomes Y. This confirms that the shift of minus 1 has been applied correctly in generating the code word OQX.

Why Other Options Are Wrong:
The options BJX, LFT, PSU, and OQY cannot consistently be obtained by shifting each letter of PRY backward by exactly 1 position. Some of these options involve either a different shift magnitude or movement in the wrong direction in the alphabet. Hence, they do not obey the uniform rule verified from REGAINS → QDFZHMR.

Common Pitfalls:
Students sometimes miscalculate the position of letters near the ends of the alphabet, especially when wrapping around from A to Z or Z to A. Others assume a forward shift without checking all pairs. Carefully computing positions and verifying the same shift for every letter in the example avoids these errors.

Final Answer:
The word "PRY" is written as OQX in the given code language.