The Diameter of a Carbon Atom Is Approximately 140 Pm,whereas $\times$

The diameter of a carbon atom is approximately 140 pm,whereas the diameter of a pencil lead is approximately 0.7 mm.How many carbon nuclei would be required to span 0.70 mm? The radius of the nucleus is approximately 10,000 times smaller than the radius of an atom.

A) 5 $\times$ 10⁹ nuclei
B) 5 $\times$ 10¹⁰ nuclei
C) 5 $\times$ 10¹² nuclei
D) 5 $\times$ 10¹³ nuclei
E) 5 $\times$ 10¹⁵ nuclei