In the analogy CPR : ERT :: DQS : ?, which of the following three letter groups best completes the proportion based on the alphabetic pattern used?

Introduction / Context:
This is a letter analogy question. We are given one pair of related letter groups, CPR and ERT, and asked to apply the same transformation to another starting group, DQS. The aim is to find the resulting group that preserves the same relationship. Such analogies test your ability to detect consistent letter shifts in the alphabet.

Given Data / Assumptions:
Given pair: CPR corresponds to ERT.
Target transformation: DQS should correspond to an unknown group following the same rule.
Options: FSU, FTU, ESV, ETV, FGV.
We assume positions from A as 1 to Z as 26.

Concept / Approach:
The method is to examine how each letter in CPR changes to produce ERT. We then apply the same letter shifts to DQS. Usually this involves adding or subtracting a fixed number of positions in the alphabet. Each position within the three letter group is often shifted by the same amount.

Step-by-Step Solution:
Step 1: Convert CPR to positions: C is 3, P is 16, R is 18. Step 2: Convert ERT to positions: E is 5, R is 18, T is 20. Step 3: Compute differences: from C to E is plus 2, from P to R is plus 2, from R to T is plus 2. Therefore the pattern is a shift of +2 positions for each letter. Step 4: Apply this pattern to DQS. Positions: D is 4, Q is 17, S is 19. Adding 2 to each, we get 6, 19, and 21. Step 5: Convert these positions back to letters: 6 is F, 19 is S, and 21 is U, giving the group FSU.

Verification / Alternative check:
We can verify by checking whether any other option fits the +2 pattern. FTU would require moving from D to F (+2), Q to T (+3), and S to U (+2), which is inconsistent. ESV and ETV show mixed steps that do not consistently match +2 for all three letters. FGV also does not apply the same fixed shift. Only FSU cleanly represents adding 2 positions to each letter of DQS.

Why Other Options Are Wrong:
FTU: Middle letter T does not come from Q by adding 2, so this breaks the uniform transformation.
ESV and ETV: These groups involve irregular jumps that are not equal across all positions and do not match the original analogy pattern.
FGV: None of its letters correspond to a uniform +2 shift from D, Q, and S.

Common Pitfalls:
A common error is to only compare the first letters and ignore the rest. Another pitfall is to miscount the alphabet positions, especially when letters are near the end. To avoid mistakes, always convert letters to numeric positions, calculate differences carefully, and ensure that the same rule applies to every position in the group.

Final Answer:
The group that completes the analogy is FSU.