\textbf{204.} The electronic configuration of the last shell of which element is similar to the electronic configuration of the last shell of atom $\text{K}_{19}$?
(1) $_{29}\text{A}$ \hfill (2) $_{31}\text{D}$ \hfill (3) $_{37}\text{X}$ \hfill (4) $_{31}\text{Z}$
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