Answer:
The correct answer is option (2).
Step-by-step explanation:
Carbon-12:
Atomic Number = 6
Mass number = 12
Nuclear charge = number of protons = +6
Number of electrons = 6
Carbon-14:
Atomic Number = 6
Mass number = 14
Nuclear charge = number of protons = +6
Number of electrons = 6
An atom of carbon-12 and an atom of carbon-14 only differ in their mass number as C-12 has mass number of 12 and C-14 has mass number of 14.