The relative density of gold is 19.3. Its density in SI unit is:

Correct option is A

Relative density is the ratio of density of substance to the density of reference material.

​$$\text{Relative density} = \frac{\text{Density of substance}}{\text{Density of water}}$$

$$\text{Given, Relative density of gold} = 19.3 \\\text{Density of water} = 1000 \, \text{kg/m}^3$$

$$\text{Density of Gold} = 19.3 \times 1000 \, \text{kg/m}^3 = 19.3 \times 10^3 \, \text{kg/m}^3$$​​​​