In a certain code language, the word CERTAIN is written as DFSTBJO. Using the same coding rule, how is the word CRICKET written in that language?

Introduction / Context:
This question is about a simple substitution code where each letter of a word is replaced by another letter according to a fixed algebraic rule on alphabet positions. The example shows how CERTAIN becomes DFSTBJO. We must detect the underlying transformation and then apply it to the new word CRICKET. Such questions usually involve adding or subtracting a constant from the alphabet index of each letter.

Given Data / Assumptions:

• Original word: CERTAIN.
• Coded word: DFSTBJO.
• Target word: CRICKET.
• The same coding rule applies to both words.
• We work with the standard English alphabet A to Z and their positions from 1 to 26.

Concept / Approach:
By pairing letters from CERTAIN and DFSTBJO, we can check how many positions each letter is shifted. For most pairs, C to D, E to F, R to S, A to B, I to J, and N to O, the transformation is a shift of plus one in the alphabet. The letter T remains T, which is a slight irregularity but does not affect the general pattern. Since exam questions usually target a simple rule, we adopt the basic pattern that each letter shifts to the next letter in the alphabet. We then apply this uniform plus one shift to each letter of CRICKET.

Step-by-Step Solution:
Step 1: Assign positions: C is 3, E is 5, R is 18, T is 20, A is 1, I is 9, and N is 14.Step 2: Check the coded letters: D is 4, F is 6, S is 19, T is 20, B is 2, J is 10, and O is 15.Step 3: The pattern is that most letters increase by one position: C to D, E to F, R to S, A to B, I to J, N to O, with T remaining unchanged.Step 4: Apply this rule to CRICKET. C, R, I, C, K, E, T become D, S, J, D, L, F, U respectively by shifting each letter one step forward.Step 5: Thus CRICKET is coded as DSJDLFU.

Verification / Alternative check:
We can verify by reversing the shift. Taking DSJDLFU and shifting each letter back by one, D to C, S to R, J to I, D to C, L to K, F to E, and U to T, we recover CRICKET. Similarly, reversing DFSTBJO by one gives CERTAIN, except for the unchanged T case, which still maps correctly. This confirms that the intended rule is a plus one shift and that DSJDLFU is the only option consistent with this mapping.

Why Other Options Are Wrong:
The option DSJBLFU differs in the middle letters and would not revert to CRICKET when shifted back. The options DSJCLFU and DSJCLFV similarly introduce letters that do not match the plus one pattern at all positions and would encode some different word. The extra distractor DTKDMSG is not consistent with a uniform single step shift from CRICKET and therefore cannot represent the same coding rule. Only DSJDLFU exactly follows the shift pattern derived from the CERTAIN example.

Common Pitfalls:
Candidates sometimes mix up plus one and minus one shifts, or they calculate the shift correctly for a few letters but make a small mistake in the middle of the word. Another issue is ignoring an irregular letter like T in the example and assuming a more complicated rule than needed. Focusing on the majority pattern and checking the reverse transformation helps avoid overcomplication and small arithmetic errors.

Final Answer:
Using the same plus one alphabet shift used to code CERTAIN, the word CRICKET is written as DSJDLFU.