Answer:
To determine which substance has the maximum number of molecules, we need to compare the number of moles for each substance.

Step 1: Calculate the number of moles for each substance using the formula:
Number of moles = Mass / Molar mass

Step 2: Calculate the number of molecules using Avogadro's number:
Number of molecules = Number of moles * Avogadro's number

Let's calculate the number of moles and number of molecules for each substance:

a) 44g CO2:
Molar mass of CO2 = 12.01 g/mol (carbon) + 2 * 16.00 g/mol (oxygen) = 44.01 g/mol
Number of moles = 44g / 44.01 g/mol = 1 mole
Number of molecules = 1 mole * 6.022 x 10^23 molecules/mole = 6.022 x 10^23 molecules

b) 48g O3:
Molar mass of O3 = 3 * 16.00 g/mol (oxygen) = 48.00 g/mol
Number of moles = 48g / 48.00 g/mol = 1 mole
Number of molecules = 1 mole * 6.022 x 10^23 molecules/mole = 6.022 x 10^23 molecules

c) 8g H2:
Molar mass of H2 = 2 * 1.01 g/mol (hydrogen) = 2.02 g/mol
Number of moles = 8g / 2.02 g/mol ≈ 3.96 moles
Number of molecules = 3.96 moles * 6.022 x 10^23 molecules/mole ≈ 2.39 x 10^24 molecules

d) 64g SO2:
Molar mass of SO2 = 32.07 g/mol (sulfur) + 2 * 16.00 g/mol (oxygen) = 64.07 g/mol
Number of moles = 64g / 64.07 g/mol ≈ 1 mole
Number of molecules = 1 mole * 6.022 x 10^23 molecules/mole = 6.022 x 10^23 molecules

Conclusion:
From the calculations above, we can see that option 'C' (8g H2) has the maximum number of molecules, which is approximately 2.39 x 10^24 molecules. This is because hydrogen (H2) has a lower molar mass compared to the other substances, allowing for a larger number of moles and molecules with the same mass.