A 50-Liter Gas Tank Holds 1

A 5.0-liter gas tank holds 1.4 moles of helium (He) and 0.70 moles of oxygen (O₂) ,at a temperature of 260 K.The atomic masses of helium and oxygen are 4.0 g/mol and 16.0 g/mol,respectively.Avogadro's number is 6.022 × 10²³ molecules/mol and the Boltzmann constant is .The total random translational kinetic energy of the gas in the tank is closest to

A) 6.8 kJ.
B) 6.1 kJ.
C) 7.6 kJ.
D) 8.3 kJ.
E) 9.1 kJ.