In a given substance, as the temperature of a substance increases, the volume of that substance
a: decreases
b: flutuates
c: increases
d: is not affected

C: increases

Explanation:

Temperature is directly proportional to volume. If the temperature of a substance increases, the volume also increases. If the temperature decreases the volume also decreases.

According to Charles's law "the volume of fixed mass of gas varies directly as its absolute temperature if the pressure remains constant". Although this is an ideal gas law, it is also applicable to most substances.

As the temperature is raised, the volume also behaves proportionally that way.  

the density of gold = 19.3 g/cm3

the relation between density and mass and volume is

density = mass / volume

given :

mass of gold = 13 g

density = 13g / volume = 19.3

volume = 13 /19.3 = 0.67 cm^3

thus volume of gold nugget = 0.67 cm^3