Select the letter-cluster from among the given options that can replace the question mark (?) in the following series.AGMST, CIOUV, EKQWX, ?

Let's break down the progression position by position:1st letter: A $\to$ C $\to$ E $\to$ ?$\text{A}(1)+2=\text{C}(3)$$\text{C}(3)+2=\text{E}(5)$$\text{E}(5)+2=\mathbf{G}(7)$ 2nd letter: G $\to$ I $\to$ K $\to$ ?$\text{G}(7)+2=\text{I}(9)$$\text{I}(9)+2=\text{K}(11)$$\text{K}(11)+2=\mathbf{M}(13)$ 3rd letter: M $\to$ O $\to$ Q $\to$ ?$\text{M}(13)+2=\text{O}(15)$$\text{O}(15)+2=\text{Q}(17)$$\text{Q}(17)+2=\mathbf{S}(19)$ 4th letter: S $\to$ U $\to$ W $\to$ ?$\text{S}(19)+2=\text{U}(21)$$\text{U}(21)+2=\text{W}(23)$$\text{W}(23)+2=\mathbf{Y}(25)$ 5th letter: T $\to$ V $\to$ X $\to$ ?$\text{T}(20)+2=\text{V}(22)$$\text{V}(22)+2=\text{X}(24)$$\text{X}(24)+2=\mathbf{Z}(26)$ Combining these results, the missing cluster is GMSYZ.