Given the pattern in the provided combinations, how would you express the combination represented by '?' ?
$$\text{AZ3B, CY6D, EX9F, ?}$$

Let's break down each component of the terms in the series:
1. First Letter: $\text{A}\stackrel{+2}{\to }\text{C}\stackrel{+2}{\to }\text{E}\stackrel{+2}{\to }\mathbf{G}$
2. Second Letter: $\text{Z}\stackrel{-2}{\to }\text{X}\stackrel{-2}{\to }\text{V}\stackrel{-2}{\to }\mathbf{T}$ (Wait, let's re-verify the given sequence from image: AZ3B, CY6D, EX9F...)
* Ah, let's look closer at the image sequence:
* First Letter: $\text{A}(+2)\to \text{C}(+2)\to \text{E}(+2)\to \mathbf{G}$
* Second Letter: $\text{Z}(-1)\to \text{Y}(-1)\to \text{X}(-1)\to \mathbf{W}$
* Number: $3\stackrel{+3}{\to }6\stackrel{+3}{\to }9\stackrel{+3}{\to }12$
* Last Letter: $\text{B}(+2)\to \text{D}(+2)\to \text{F}(+2)\to \mathbf{H}$

3. Combining these elements gives: $\text{G}+\text{W}+12+\text{H}=\text{GW12H}$.