Answer:
Option A
Explanation:
$Z-2 \rightarrow X, X-5 \rightarrow S, S-10 \rightarrow I, I-17 \rightarrow R,$
$R-26 \rightarrow R, R-37 \rightarrow G, G-50\rightarrow I$
Note that the numbers representing the difference between the consecutive terms of the series again forms a series -2,5,10,17,26,37,50- in which the pattern is +3, +5, +7, +9, +11, +13.