String manipulation on 'CONCENTRATION' – Reverse the last four letters and then reverse the preceding three letters; in the new arrangement, counting from the rightmost end, which letter is in the 8th position?

Introduction / Context:
This problem tests careful application of successive string operations and then positional counting from the end. We start with the word “CONCENTRATION.” The instruction is: reverse the last four letters; then reverse the next three letters immediately preceding those last four; finally, in the resulting string, identify the 8th letter from the rightmost end. Such questions reward orderly, index-based work to avoid transposition mistakes.

Given Data / Assumptions:

• Original: C O N C E N T R A T I O N (13 letters).
• Indices (1-based): 1:C, 2:O, 3:N, 4:C, 5:E, 6:N, 7:T, 8:R, 9:A, 10:T, 11:I, 12:O, 13:N.
• “Last four letters” = positions 10–13 (T I O N).
• “Next three” preceding those = positions 7–9 (T R A).

Concept / Approach:
Apply the two reversals as separate, explicit steps on their respective contiguous blocks while keeping all other letters unchanged. After both operations, write the final string and count from the rightmost character to locate the 8th position.

Step-by-Step Solution:
Step 1 (reverse last 4): positions 10–13 = T I O N → reversed to N O I T. New tail becomes N O I T.Step 2 (reverse preceding 3): positions 7–9 = T R A → reversed to A R T. Replace those positions accordingly.Unchanged prefix 1–6: C O N C E N.Final string left→right: C O N C E N A R T N O I T (i.e., “CONCENARTNOIT”).Count from the rightmost end: 1:T, 2:I, 3:O, 4:N, 5:T, 6:R, 7:A, 8:N → the 8th from the right is N.

Verification / Alternative check:
Index mapping from the right shows that the 8th from right equals overall position 6 from the left in a 13-letter word (since 13 − 8 + 1 = 6). Looking at the final string, position 6 is indeed N. Both counting methods align.

Why Other Options Are Wrong:

• “T” corresponds to multiple other positions but not the 8th from the right after the specified operations.
• “0/1” are not letters; they are distractors sometimes used to check attention to instructions.
• “C” does not appear at the computed 8th-from-right slot.

Common Pitfalls:
Reversing the wrong blocks (e.g., mislocating the “next three”), reversing the entire suffix by mistake, or counting from the left instead of from the right for the final step. Writing indices explicitly prevents such errors.

Final Answer:
N