Write the nuclear reaction for $\alpha$ delay of $_{88} Ra^{226}$

Question

$\begin{array}{1 1} _{88}{Ra} ^{226} \to _{86} R_n^{222} +_2 He ^{4} \\ _{88}{Ra} ^{226} \to _{86} U^{222} +_2 He ^{4} \\ _88{Ra} ^{226} \to _{86} P_o^{222} +_2 He ^{4} \\ _88{Ra} ^{226} \to _{86} R_n^{222} +_2 He ^{4} \end{array}$