Select the related group of letters that completes the analogy: EFG is related to OPQ in the same way as which of the following letter groups is related to STU?

Introduction / Context:
This analogy involves three letter sequences and a fixed shift in alphabet positions. The pair EFG : OPQ suggests that each letter in EFG has been moved forward by the same number of positions to form OPQ. The task is to find the letter group that would need the same shift to reach STU. It is a standard coding style question where a consistent numerical shift in the alphabet is used across all letters.

Given Data / Assumptions:
- First triple: EFG, second triple: OPQ.
- The alphabet positions are A = 1 to Z = 26.
- We must determine the shift applied to E, F, and G to obtain O, P, and Q respectively.
- STU is the target triple in the second pair, and we must find the triple that transforms into STU under the same shift.

Concept / Approach:
Convert letters to numeric positions. E is 5, F is 6, G is 7. O is 15, P is 16, Q is 17. The shift from E to O is plus ten. From F to P is also plus ten, and from G to Q is plus ten. This gives a consistent pattern: add ten to the position of each letter. Now we work backwards for the second pair. For STU, S is 19, T is 20, and U is 21. To find their original letters, subtract ten from each: 19 minus ten is 9, 20 minus ten is 10, and 21 minus ten is 11. The 9th, 10th, and 11th letters are I, J, and K, so the required triple is IJK.

Step-by-Step Solution:
Step 1: Note the positions of E, F, G as 5, 6, and 7. Step 2: Note the positions of O, P, Q as 15, 16, and 17. Step 3: Compute the differences. 15 minus 5, 16 minus 6, and 17 minus 7 all equal ten. Step 4: Conclude that each letter in the first triple is shifted forward by ten positions to get the second triple. Step 5: Apply the reverse operation to STU. S(19) minus ten is 9, T(20) minus ten is 10, U(21) minus ten is 11. Step 6: Convert 9, 10, and 11 back to letters. They are I, J, and K. Step 7: Check options and find that IJK is given as option D, which must be the correct answer.

Verification / Alternative check:
To verify, we can also apply the forward shift of plus ten to IJK and see if it produces STU. I(9) plus ten is S(19), J(10) plus ten is T(20), and K(11) plus ten is U(21). This confirms that IJK : STU follows exactly the same transformation as EFG : OPQ. None of the other options, when shifted by ten, yields STU, so they cannot complete the analogy.

Why Other Options Are Wrong:
Option A, GHI, shifted by ten gives QRS, not STU. Option B, LMN, yields VWX, and option C, JKL, yields TUV. These do not match the required second triple. Since the core of the analogy is the fixed plus ten shift, only the triple that maps to STU under this operation is acceptable.

Common Pitfalls:
Common errors include miscounting alphabet positions or failing to notice that the same shift is applied to every letter. Some test takers may try to guess based on how the sequences look or sound, without checking numeric positions. To avoid such mistakes, always convert letters to numbers and calculate differences for each position. Once you see a consistent shift, use it strictly on all letters involved in the analogy.

Final Answer:
Applying a constant shift of ten letters, EFG becomes OPQ and IJK becomes STU. Thus, the correct related group of letters is IJK, and option D is correct.