Answer: Gold.
Explanation: Water, CO2, and table salt are compounds. They are composed of two or more separate elements; a mixture, where as gold is neither.
Avagadros law states that volume of gas is directly proportional to number of moles of gas at constant pressure and temperature.

where V -volume , n - number of moles
parameters for the first instance are on the left side and parameters for the second instance are on the right side of the equation
substituting these values in the equation

V = 44.8 L
answer is C. 44.8 L
The correct answer is C. Litmus Indicator
It has a pb of 69c from google