A Container Is Filled with a Mixture of Helium and Oxygen

Multiple Choice

A container is filled with a mixture of helium and oxygen gases. A thermometer in the container indicates that the temperature is 22°C. Which gas molecules have the greater average speed?

A) The helium molecules do because they are monatomic.
B) It is the same for both because the temperatures are the same.
C) The oxygen molecules do because they are diatomic.
D) The oxygen molecules do because they are more massive.
E) The helium molecules do because they are less massive.