Which Type of Membrane Transport Will Still Be Possible When

Which type of membrane transport will still be possible when there is not enough oxygen available for producing adequate levels of ATP, such as during anaerobic exercise or in high altitudes ?

A) flow of ions through channels
B) transport of glucose by GLUT carriers
C) pumping Na⁺ and K⁺ by the Na⁺/K⁺ ATPase
D) All of the choices are correct.
E) both flow of ions through the channels and transport of glucose by GLUT carriers