This is what your screen should look like. start with hydrogen -1 and drag 2 neutrons over the to the nucleus. what happens to the hydrogen-1 atom? see picture in comments

A tritium is produced.

Explanation:

Combining two additional neutrons to the nucleus of the hydrogen atom makes it a tritium, Hydrogen-3.

   neutron is designated  ¹₀n; this shows a mass number of 1 and no atomic number

  Hydrogen-1 is designated as ₁¹H; a mass number of 1 and atomic number of 1. This particle is actually more like a proton.

        Combining both:

                  ₁¹H + 2¹₀n → ³₁H

This is a nuclear reaction and in balancing such reaction equation, mass numbers and atomic numbers must be conserved.

i think   the answer is c hope i'm right