Two-letter terms: first letter +1, second letter -1 (AZ, BY, CX ...)

The same question, asked 4 times: 19 Sep 2025 S2*, 20 Sep 2025 S1, 24 Sep 2025 S3*, 26 Sep 2025 S2. Every wording below, oldest first.

Try each one first, then open its answer.

Question 1
19 Sep 2025 S2
20 $Select the letter-cluster from among the given options that can replace the question mark (?) in the following series: AZ, BY, CX, ?$
Tap an option to check your answer.
Question 2
20 Sep 2025 S1
15 $Complete the series : AZ, BY, CX, DW, ?$
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Question 3
24 Sep 2025 S3
20 $What comes next? KJ, LI, MH, ?$
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Question 4
26 Sep 2025 S2
16 $What comes next? AZ, BY, CX, DW, ?$
Tap an option to check your answer.

Question 1