Write nuclear equation for $\alpha$ decay of $_{94} Pu ^{242}$

Question

$\begin{array}{1 1} 94_Pu^{242} \to {92}Th^{238}+_2He^4 \\ 94_Pu^{242} \to {92}U^{238}+_2He^4 \\ 94_Pu^{242} \to {92}R_n^{238}+_2He^4 \\ 94_Pu^{242} \to {92}X^{238}+_2He^4 \end{array}$