)Experimental evidence indicates that the nucleus of an atom A)contains most of the mass of the atom
B)contains a small percentage of the mass of the atom
C)has no charge
D)has a negative charge

A (contains most of the mass of the atom)

Evidence has it that a proton is about 2000 times as massive as an electron.

And there is usually multiple protons and neutrons in the nucleus

From what I just said, you can say that B is wrong

C however is also wrong because protons have a +charge and neutrons are neutrle which means you always have a charge > (greater than) 0

And D is wrong because electrons (which are not in the nucleus) have a neg charge. and protons have a + charge and are in the nucleus

So your answer is A

Hope it helped

Spiky Bob