Answer:
the last option is correct
Step-by-step explanation:
see I won't explain all the points but will tell you the concept being used.
- protons and neutrons are inside the nucleus in an atom while the electrons are outside the nucleus.
- the mass number of an atom is equal to the sum of number of electrons and neutrons in an atom
- atomic number is equal to the number of electrons which is equal to the number of protons in an atom
- no. of electrons/ protons is always less than that of neutrons and they're almost equal( a large difference ain't obtained between the number of electrons and that of neutrons.
since, the rest of the options are violating the above rules they're incorrect