$\text{ Which nuclear reaction is an example of }\mathrm{\alpha }\text{-emission? }$

• A

  ${ }_{92}^{235}\mathrm{U}{⟶}_{90}^{231}\mathrm{Th}{+}_2^4\mathrm{He}$

• B

  ${ }_{34}^{75}\mathrm{Se}{⟶}_{35}^{75}\mathrm{Br}{+}_{-1}^0\mathrm{e}$

• C

  ${ }_7^{14}\mathrm{N}{+}_2^4\mathrm{He}{⟶}_8^{17}\mathrm{O}{+}_1^1\mathrm{H}$

• D