We must select the correct option.
In order to determine which subatomic particle has no charge we need to review the definition of each of the options
Electron: is a negatively charged subatomic particle. It can be either free (not attached to any atom), or bound to the nucleus of an atom.
Neutron: neutral subatomic particle that is a constituent of every atomic nucleus except ordinary hydrogen.
Proton: stable subatomic particle that has a positive charge equal in magnitude to a unit of electron charge.
Ion: is a charged atom or molecule. It is charged because the number of electrons do not equal the number of protons in the atom or molecule.
Now, analyzing the definitions we can see that Neutron is a neutral subatomic particle. That means that a neutron has no charge.
Then, the answer is:
B.) Neutron