In this letter pair analogy, WD is related to TF by a specific forward and backward shift; using the same pattern, choose the pair that completes the analogy: WD : TF :: TG : ?

Introduction / Context:
This question uses an alphabetic analogy between pairs of letters. The pair WD changes to TF using a specific rule applied to each letter. You must detect that rule and then apply it to the second pair, TG, to find the correct related pair from the options. These questions improve your skill in tracking multiple shifts simultaneously.

Given Data / Assumptions:

• The alphabet is numbered from A = 1 to Z = 26.
• WD is transformed into TF.
• The transformation is consistent across the letters within the pair.
• The same two letter operation is applied to TG.

Concept / Approach:
To solve this, we analyse each position separately. It is common for the first and second letters of a pair to have different shifts. So we find the change from W to T and from D to F. Once we identify both shifts, we apply them to the letters T and G in the second pair. We must preserve the order and use the same amount of addition or subtraction.

Step-by-Step Solution:
Step 1: Note the positions of W and D. W is the 23rd letter, and D is the 4th.Step 2: Find the positions of T and F. T is the 20th letter, and F is the 6th.Step 3: Compute the shift for the first letter: W (23) to T (20) is a change of minus 3 positions.Step 4: Compute the shift for the second letter: D (4) to F (6) is a change of plus 2 positions.Step 5: Infer the rule: first letter moves back 3 positions in the alphabet, while the second letter moves forward 2 positions.Step 6: Apply this rule to TG. T is the 20th letter, and G is the 7th.Step 7: Move T back by 3 positions: 20 minus 3 equals 17, which corresponds to Q.Step 8: Move G forward by 2 positions: 7 plus 2 equals 9, which corresponds to I.Step 9: The resulting pair is QI, which matches option B.

Verification / Alternative check:
To verify, we simply reapply the same logic. WD to TF uses minus 3 on the first letter and plus 2 on the second. Applying minus 3 and plus 2 to T and G gives QI consistently. Alternatives like QR, IQ and IP do not arise from these exact shifts. Therefore our pattern is both consistent and unique.

Why Other Options Are Wrong:
Option A, QR, requires adding or subtracting different values that do not match the WD to TF transformation. Option C, IQ, reverses the correct pair and violates the position based rule. Option D, IP, introduces P, which cannot be obtained by adding 2 to G. Since none of these maintain the precise minus 3 and plus 2 pattern, they are incorrect.

Common Pitfalls:
Students often assume the same shift is used for both letters or fail to consider backward shifts. Another mistake is to swap the order of letters or pick a visually appealing pair without verifying numerical positions. The safest method is always to convert letters to numbers, compute the exact changes and replicate them carefully.

Final Answer:
Under the same pattern, TG transforms into QI, so option B is correct.