Answer:
The atoms are called A) Isotopes.
Step-by-step explanation:
When the atom of one element shows variations in its neutron composition, it is called as isotopes. In such elements, the number of proton remains same whereas the number of neutron varies. For example, hydrogen has two isotopes namely Deuterium, Protium, and Tritium.
In general, the chemical properties of isotopes of one element remain same whereas the physical property differs. It is because the physical property relies upon the mass of the compound. The isotopes of hydrogen are exceptional to this case.