What will replace '?' in the following alphanumeric series?

C2X, G3T, K5P, O7L, ?, W13D

Looking at the series: C2X, G3T, K5P, O7L, ?, W13D

Each term has three components: a letter, a number, and another letter. Let's analyze each component separately.

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First letter pattern: C, G, K, O, ?, W

Converting to positions in the alphabet:

• C = 3
• G = 7
• K = 11
• O = 15
• ? = 19
• W = 23

The difference between consecutive terms is 4.

Position 19 corresponds to the letter S.

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Number pattern: 2, 3, 5, 7, ?, 13

These are prime numbers in sequence: 2, 3, 5, 7, 11, 13

The missing number is 11.

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Last letter pattern: X, T, P, L, ?, D

Converting to positions in the alphabet:

• X = 24
• T = 20
• P = 16
• L = 12
• ? = 8
• D = 4

The difference between consecutive terms is -4.

Position 8 corresponds to the letter H.

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The missing term is S11H.

Therefore, the answer is Option 2: S11H.