Answer
The correct choice is (a) $ ^{130}_{\space52}Te+ n → ^{131}_{\space52}Te $
Work Step by Step
To make the isotope $^{131}_{\space52}Te$, we need to make sure,
1. The source has a neutron because the atom is neutral and the proton number remains the same.
2. The source has lesser nucleon number since adding one neutron will result in increasing in 1 nucleon number.
We write the possible nuclear reaction that occurs
$ ^{130}_{\space52}Te+ n → ^{131}_{\space52}Te $
The correct choice is (a) because it has both conditions at (1) and (2) and satisfies the equation.
