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

Options

(a) ₃₄Se⁷⁴,₃₁Ga⁷¹
(b) ₃₈Sr⁸⁴,₃₈Sr⁸⁶
(c) ₄₂Mo⁹²,₄₀Zr⁹²
(d) ₂₀Ca⁴⁰,₁₆S³²

Correct Answer:

₃₄Se⁷⁴,₃₁Ga⁷¹

Explanation:

Isotones means number of neutron remains same.