In the series A2BC, ?, ABC4, A5BC, which term should replace the question mark so that the pattern in the position of the digit 2, 3, 4, 5 is maintained?

Introduction / Context:
This problem uses an alphanumeric pattern involving the letters A, B, C and digits 2, 3, 4, 5 placed in different positions. The goal is to identify not only the correct digit to insert but also the exact position in which it must appear so that the overall sequence respects a hidden positional rule.

Given Data / Assumptions:
- The visible terms are: A2BC, ?, ABC4, A5BC.- Digits 2, 3, 4, 5 appear one by one across these terms.- The sequence suggests that both the digit value and its position in the four character pattern are important.

Concept / Approach:
We first list the structure of each term and track where the digit is placed. For A2BC and A5BC, the digit appears in the second position, while in ABC4 it appears at the end. This indicates that the position of the digit is not fixed and may be moving in a systematic way. We must find a placement for the digit 3 that bridges the pattern between A2BC and ABC4 logically.

Step-by-Step Solution:
- The set of digits involved is 2, 3, 4, 5, which should all appear exactly once.- A2BC already uses digit 2, ABC4 uses digit 4, and A5BC uses digit 5, so the missing term must use digit 3.- Consider positions: A2BC has digit at second position, ABC4 has digit at fourth position, A5BC again at second position.- A natural pattern is to let the digit move gradually across the middle positions while preserving A, B, C in the remaining places.- Placing 3 in the third position gives AB3C, which fits smoothly between A2BC and ABC4 as the digit shifts towards the end.- Hence AB3C is a consistent and systematic choice for the missing term.

Verification / Alternative check:
- Check that each digit 2, 3, 4, 5 appears exactly once across the four terms.- Confirm that A, B, C always occupy three of the four positions and that the digit occupies the remaining one.- The progression A2BC, AB3C, ABC4, A5BC gives a natural shifting of the digit position from earlier to later positions and back, while covering all digits.

Why Other Options Are Wrong:
- A3BC keeps the digit in the second position, offering no positional change between A2BC and the next term.- ABC3 places the digit at the end like ABC4, making the two middle terms too similar in structure.- A2B3C4 introduces extra digits and completely breaks the intended one-digit-per-term pattern.- Only AB3C uses digit 3 exactly once and provides a logical positional transition.

Common Pitfalls:
Many candidates focus only on which digit is missing and ignore the positional structure, leading them to choose any option containing 3. Some also overlook that each term should contain only one digit. Always check both which symbol is used and where it is placed in pattern-based alphanumeric series.

Final Answer:
The correct term that should replace the question mark is AB3C, so the correct option is AB3C.