A radioactive nucleus \( D ^{\prime} \) 's decaying in the following way :
\[
\stackrel{235}{92} D _{\underline{\alpha} \text { decay }}, D _{1}, \beta \text { decay }, D _{2} \stackrel{\alpha \text { decay }}{\longrightarrow} D _{3}, \text { y decay }, D _{4}
\]