Answer: option B.with “Inside the nucleus,” because the particle is a neutron.
Explanation:
You have to <u><em>complete this table</em></u>:
mass | location | charge
1 ? Has no charge
<em>The atom</em> is constituted by <em>3 subatomic particles</em>, namely electron, proton, and neutron.
Since the gold foil experiment performed by Geiger and Marsden (1909), who collaborated with Ernest Rutherford, it was stablished that the atom contains a dense positively charged nucleus, which has almost all the mass of the atom.
The positive charge comes from the subatomic particle named proton.
A few time later, a second subatomic particle inside the nucleus, was discovered. This particle has not charge and has almost the same mass than the proton. Because the absence of charge it was named <em>neutron</em>.
Hence, the relative masses of the protons and neutrons are 1 / 1. As said, both are in the <em>nucleus</em>, and while the proton has positive charge, the <em>neutron has no charge</em>. So, <em>the table is completed with inside the nucleus, because the particle is a neutron</em><em>:</em>
mass | location | charge
1 inside the nucleus Has no charge