Read the passage and answer the question.

Experiments performed have showed that radioactivity is a nuclear phenomenon in which an unstable nucleus undergoes a decay. This is referred to as radioactive decay. Three types of radioactive decay occur in nature :

1. α-decay
2. β-decay
3. γ-decay

 Consider that ₉₂U²³⁸ decays via alpha decay. 

Which of the following can be a possible daughter nuclei?

₉₀Th²³⁴

In alpha decay, mass no. falls by 4 and atomic no. falls by 2