The correct option is A 10−15
As we know,
Radius of nucleus (r1) is in the order of 10−13cm and radius of an atom (r2) is 10−8cm.
Volume of nucleus = 43π(r1)3
Total Volume of atom = 43π(r2)3
So, volume fraction = volume of nucleusTotal volume of atom=4/3π(10−13)3cm34/3π(10−8)3cm3=10−15