Answer the following question given this paragraph: 

Note that in Table 14.3, the best thermal conductors—silver, copper, gold, and aluminum—are also the best electrical conductors, again related to the density of free electrons in them. Cooking utensils are typically made from good conductors.


Q: The best thermal conductors are also the best conductors of what, which is also related to the density of free electrons in them?


A:
electricity