The correct answer will be A;
A) The number of protons in the nucleus does not equal the number of neutrons.
A=mass number:
Z=atomic number (= number of protons)
N=number of neutrons:
A=Z+N
If the number of protons in the nucleus is equal the number of neutrons , we would have an even mass number; because Z=N=x; then A=x+x=2x (this is always an even number) but 23 is an odd number, therefore the number of protons in the nucleus does not equal the number of neutrons.
