The nuclei of which one of the following pairs of nuclei are isotones?

• Correct answer
  A

  ${ }_{34} \mathrm{Se}^{74},{ }_{31} \mathrm{Ga}^{71}$
• B

  ${ }_{38} \mathrm{Sr}^{84},{ }_{38} \mathrm{Ga}^{86}$
• C

  ${ }_{42} \mathrm{Se}^{92},{ }_{40} \mathrm{Ga}^{92}$
• D

  ${ }_{20} \mathrm{Se}^{40},{ }_{16} \mathrm{Ga}^{12}$

Hence, the correct answer is option: 'A'.