Which of the following is true for a reliable scientific source?
It cites logic
It cites opinions.
It cites valid data.
It cites common sense.

It cites valid data

Explanation:

It clearly shouldn't cite opinions cause then that isn't science. Every thing else seems like an okay answer but it cites valid data is the best answer since the data should be valid no matter what.

it's filtration, but this is an assumption so my apologies if i got this

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