A sealed 10.0 L flask at 400 K contains equimolar amounts of ethane and propanol in gaseous form. Which of the following statements concerning the average molecular speed of ethane and propanol is true?

(A) The average molecular speed of ethane is less than the average molecular speed of propanol.
(B) The average molecular speed of ethane is greater than the average molecular speed of propanol.
(C) The average molecular speed of ethane is equal to the average molecular speed of propanol.
(D) The average molecular speeds of ethane and propanol cannot be compared without knowing the total pressure of the gas mixture.