Molecules

How many molecules are present in 475 mL of CO2 at STP?

a. 2.86 x 10 to the power of 23 molecules of CO2
b. 0.0212 molecules of CO2
c. 6.50 x 10 to the power of 21 molecules of CO2
d. 1.28 x 10 to the power of 22 molecules of CO2
e. 1.28 x 10 to the power of 25 molecules of CO2